On kids, I think that would be tough. I could see mine being happy to do pretty local tours, maybe more MTB oriented for the fun, stopping at lakes. Snowmobile trail kinda stuff. They get bored of riding continually though. My kids are 10-1+, the oldest is the worst, though she is athletic, interest just isn't there yet, and I don't blame her one bit. I have never seen a kid who seems to believe the bike is for racing snails, a walker can easily keep up with her.

I have read some good blogs on crazyguyonabike about families that cycled across Canada, it certainly can work.