@sandandsun: that's my attitude exactly - if you want it, this is what you have to do! But I do have a tendency to be a bit hard-line about things, especially involving not driving, and I'm never sure when I'm being *too* hard-line, kwim? And your point is good too - it's only nowadays that people think of distances like that as long (I was looking at it from his perspective). I used to walk probably 10-12 miles a day in the summer when I was a kid and thought nothing of it. It just requires a perspective shift. When I first stopped teaching and was able to walk him to school everyday (.6 miles one way - not far at all!) he complained bitterly about it, but now he's used to walking to school no matter what the weather. He did the same when I insisted that we only walk to his doctor's office (4 miles round-trip), and now he sees that as normal too.
@donovan: that's a good thought. Maybe a new (used) bike would be a good incentive. He's outgrown his old one, which is sized for perhaps the average 8-year-old and he is a very tall 10-year-old. When biking, he looks kind of like the cycling equivalent of a giant clown in a tiny car!