I really like this concept~ It seems like it would have all the action of extreme sports games, but with points where you can "hop off" to plan your next moves or even just take a break and absorb the environment. And so long as you can reasonably place the pipes/rails, you can take the player to any kind of location- that seems really cool!
I'd also like to say that there is something especially charming about the hand-written/drawn notes, like the idea is really laid bare here.
Great work! :D