I think it's great! One thing: if you did this with D: While, I imagine the spell would only last as long as you were walking, riding, or flying; if you stopped to rest, it would end. This D: Journey is clearly better, but I'm a little unsure about the "side trips" clause. I think you could get away with this duration lasting as long as it takes you to get to your destination as long as you are not traveling away from it, and in that case it would be okay to stop and rest without cancelling the spell as long as you don't retrace your steps. If you head off in a different direction, though, perhaps the spell should end. Interestingly, this could also cause the traveler problems with twisty roads; if there is not a generally direct route to his destination, the spell probably wouldn't work very well.