1. Sure, what I meant was "for this type of transmitter in an amateur setting and frequency range ~ 100MHz", where the antenna is usually a wire poking out and the transmitter is inside of a building
If you're doing QRP work with a professional antenna and a different frequency band (and good receptors), you're right, it can go very far
2. Yes, harmonics are an important issue. I'm not sure how they would behave in a "bad quality" circuit like this (even though "bad quality" usually mean more harmonics, the fact that you have a general purpose transistor, component leads, traces, etc, all contribute to prevent them from being amplified too much in the first place, if you're at 50MHz you'll surely have 2nd, 3rd, but probably not much beyond that)
If you're doing QRP work with a professional antenna and a different frequency band (and good receptors), you're right, it can go very far
2. Yes, harmonics are an important issue. I'm not sure how they would behave in a "bad quality" circuit like this (even though "bad quality" usually mean more harmonics, the fact that you have a general purpose transistor, component leads, traces, etc, all contribute to prevent them from being amplified too much in the first place, if you're at 50MHz you'll surely have 2nd, 3rd, but probably not much beyond that)