Consider the Camino de Santiago. I've done the last 300 km. The distance between places to stay is manageable, lots of infrastructure, lots of friendly people who could help you if you get stuck. You don't need to carry much because you sleep indoors and there is food available along the way.
The next step would be doing a hut/refuge to hut/refuge hike in the Alps. A hut/refuge is a hotel with a restaurant, private rooms, dorm rooms. They are hundreds (thousands) of them throughout the Alps. You can arrange them yourself for multiday hikes. There are an infinite number of routes, but a good starting place would be this publisher of guidebooks: https://www.cicerone.co.uk/.
Likewise, you only need to carry your lunch, but you do need more clothes because mountain weather can be unpredictable and dangerous.
I've personally done the "Tour de Vanoise" which I think is easy enough for novices and the "Stubai Hohenweg" which was definitely harder and scarier.
Actual backpacking (tent/sleeping bag, etc) is harder because you need more equipment but a good way to start in the United States might be by doing a group trip with The Sierra Club or a local club (meeetup.com) or commercial trip (REI?). I've done many Sierra Club trips.
I just want to add, for actual American-style backpacking, I think the best place for somebody who wants a managable challenge is the Sierra Nevada mountains in California, maybe a trip that would have you enter the mountains via Bishop or Kearsarge passes. Here are things that can make a backpacking trip easier or harder:
* Grizzly Bears - Some great backpacking places - the Winds, Alaska - have grizzly bears which require more discipline about food. In the Sierra, there are bears but no history of them eating people.
* Lightening - Not as likely to make you shit in your pants as the Rockies in Colorado or Wyoming.
* Water - Some great backpacking places - the Grand Canyon - you MUST get from point A to point B that day because you need that water at point B, there's no water along the route. Water sources are plentiful in the Sierra
* Where to camp - Some great backpacking places - the Grand Canyon, the Tetons - are tightly regulated by permit as to where you can camp each night, so you have to know your pace beforehand and then stick to the plan. The permit system in the Sierra is easier - you pretty much just say where you are entering and exiting
* People - if you are a novice, it's good to have other people around, not too many and not too few. There will be more or less the right number of people around in the Sierra
* Logistics - Getting to the trailheads from Bishop, CA, not so hard.
* Reward - So beautiful. You have long distance views. You aren't just in the trees.
+1 on the Sierra recommendation generally, but a couple things:
- Bears: You still need to be disciplined about food/smellables. Bear canisters are required for most of the Sierra—not bringing one is a recipe for a fine or getting escorted out by a ranger. Also, other critters are a problem. I had a raccoon steal my unguarded shorts (they had a bag of weed in the pocket) while I was sleeping, and I had to walk back to town with no pants.
- Logistics: Bishop/Kearsarge passes are quite remote and rugged, and then you’re on the PCT/JMT superhighway which is increasingly over-stressed by people. You can enter via Duck Pass or Red’s Meadow from Mammoth Lakes via public transit. The friendliest place for beginners would probably be further north in the Lake Tahoe region (e.g. Tahoe Rim Trail). Vermillion Valley Resort is a (rugged) ~1 hour drive from Fresno, and is one of the most classic congregation spots for PCT/JMT hikers and would make a great entry point. Angeles National Forest / the PCT would be a good choice for the LA area.
- Lightning/weather: The weather doesn’t care if it intimidates you or not, so you need to be prepared for anything. I didn’t bring rain pants to the desert section of the PCT and got slammed by freezing rain and had to run to avoid hypothermia. Also, please don’t do something batshit insane like go over a pass in inclement weather (I see it all the time). Here’s a document on lightning safety: https://www.nols.edu/media/filer_public/fa/96/fa96d71d-df6b-...
- Leave no trace: The Sierra is heavily impacted, so please tread lightly! In particular, don’t camp <100ft of the trail or a body of water, use Bluetooth speakers, or leave toilet paper blooms (packing it out is recommended but has low compliance, so at least mash up the TP and waste with a stick and some water to make a soupy mixture—critters like to dig up the lightly used paper). Being a wilderness ninja is cool, so read more LNT guidelines here: https://www.rei.com/learn/expert-advice/leave-no-trace.html
Regarding "Bishop/Kearsarge passes are quite remote and rugged". I'm not sure what this means, but obviously everybody has their own personal database of experiences.
The town of Bishop would be your base, and you can get there with public transportation from the airport in Reno, NV. Good stores if you need to replace equipment.
The roads to the trailheads are paved - a normal passenger car can handle the roads. Only about an hour from Bishop. There are commercial shuttles too. Even hitchhiking (I've done it, and I'm an ugly old man, and still had no trouble getting rides). The parking lots are already at high altitude, about 10,000 feet, so you only have to go another 2,000 to get over the passes.
The actual trails are in good shape, good surfaces, not narrow, not scary. There are places to camp both before and after the highest point of the passes so you can hike at your own pace. If you wanted to camp at the trailhead the night before to get adjusted to the altitude, then go just, say, just 5 miles and 1200 feet your first day, you could do that, and the trails are beautiful the whole way.
Remote = far to drive for essentially everyone (farther than Mammoth/Tahoe, even coming from Reno). Hitchhiking is not the best option to rely on. Once you’re in, you’re also the farther from help than anywhere else in the Sierra. Duck Pass and much of the Tahoe area has cell service.
Rugged = safety traversing passes can require an ice axe and/or crampons (plus the skills to use them properly), depending on the conditions. That region is at high elevation which becomes problematic for people. Lots of inexperienced backpackers get airlifted out of there because of acute altitude sickness. There is a lot of weather exposure (harder to get below treeline if a storm rolls in). Bigger stream crossings, which tend to be the most serious danger to hikers.
I don’t disagree that Bishop rules and the area is (extremely) beautiful, but it’s absolutely not the best recommendation for people who are trying to backpack for the first time. Doable? Yes. Advisable? Not really.
Regarding remote - I live in Chicago. The nearest decent place to backpack is a 7 hour drive North, and it's nice, but it's the Midwest, not the mountains. For mountains, the last time I went backpacking in the Sierra, it took me about 24 hours and a taxi, an airplaine, a bus, another bus, an uber, and one more bus to get to the trailhead. That's why for me, getting to Bishop, not so bad.
12000 feet hike for beginners??! No. Not advisable at all. Also how you react to altitude is so variable person to person and has little to do with fitness that unless you really know your altitude performance you could find yourself really ill.
I do agree that the altitude must be taken seriously. I've gotten sick. That's why I did write to camp the night before near the trailhead, at 9,000/10,000, and to be okay with NOT going over the pass on day one. Maybe that's enough to acclimate, maybe not. If you feel terrible when you wake up for day one, don't hike, go into Bishop and get a steak at the Bowling Alley. If you feel terrible while hiking on day one, turnaround. But for most people, probably, with that one night's sleep at altitude the day before the hike and a slow first day, they will be okay.
We're talking pretty much about the same altitude situation as going to a ski resort in Colorado.
The thing is, I want even the beginner to experience spectacular mountain scenery so in the USA, that usually means hiking at 10,000, above the tree line.
Getting to the Kearsarge Pass TH is a 5-hour drive from Reno. I'll go out on a limb an assume most HNers are not from Nevada. This is really a lot of driving / sitting on a bus just to try out backpacking on a weekend.
The Sierra really has the most challenging terrain of the entire trail, and is hard to get to from most major cities. Better would be to enter the trail near Mt. Baden-Powell / Wrightwood / Big Bear from Los Angeles. It also has a longer viable season than the Sierra.
Other options are Mt. Hood (near Portland), and Stevens Pass (near Seattle).
Yeah, there are a ton of good backpacks in the Cascades generally. The Mountaineers books are probably the best source of info. The only downside is you're probably (mostly) not going to be doing summits because.the higher peaks are technical climbs. (Though there are some old volcanic cores and lower peaks.)
In the east, the Appalachian Mountain Club (I'm a leader with them but don't generally do group backpacks) and the Adirondack Mountain Club also do trips. The AMC (like the Sierra Club) also does longer "adventure travel" trips which probably include backpacks.
The next step would be doing a hut/refuge to hut/refuge hike in the Alps. A hut/refuge is a hotel with a restaurant, private rooms, dorm rooms. They are hundreds (thousands) of them throughout the Alps. You can arrange them yourself for multiday hikes. There are an infinite number of routes, but a good starting place would be this publisher of guidebooks: https://www.cicerone.co.uk/. Likewise, you only need to carry your lunch, but you do need more clothes because mountain weather can be unpredictable and dangerous.
I've personally done the "Tour de Vanoise" which I think is easy enough for novices and the "Stubai Hohenweg" which was definitely harder and scarier.
Actual backpacking (tent/sleeping bag, etc) is harder because you need more equipment but a good way to start in the United States might be by doing a group trip with The Sierra Club or a local club (meeetup.com) or commercial trip (REI?). I've done many Sierra Club trips.