No disagreement here. I ended with a question as to whether there's a market; I don't know that there is.

AAA apparently has a road trip planner that's only available to members. That's one business model. :)

TripAdvisor could offer something to help promote their site. As I said above, a strong developer could crank out something better than most existing alternatives with a small time commitment.

A hobby app might be the right speed. Some suggestions I got above might end up being "good enough", though.