I have a friend who likes to go out walking for (as far as I could tell) no particular reason. He doesn't walk 7 miles, but he frequently does 2-3 mile walks. Personally I've never been one to just want to go out and walk. I've considered buying a new road bike recently, but the combination of the hills and the weather where I live will likely prevent that idea from moving ahead.
Try cycling, I find I think better on hills vs. the flat. They usually have more interested scenery and hence what I see usually triggers something in my mind; one of the reasons I like trail running.
