Some good advice for long distant walking in Lessons for Walking:
Don’t stare at your final destination. Nothing can be more depressing then to see your objective in the distance.
Take breaks. Walking isn’t very tiring, and it can be easy to forget to stop and rest.
Keep up a dialogue with yourself, or with someone who is significant to you.
Look behind you. This may sound kind of foolish at first, but it isn’t. Things don’t look the same backwards.
I used to walk a lot in my university days, but once you get a car, that’s it: I drive most everywhere. However, I was coincidently thinking about taking up long walks again (or try jogging), not just for the exercise, but for the solitude.