I road trip (with my travel trailer) quite a bit and the only app I truly miss from Android is iExit, which tells you what food and gas (and I believe other things) are available at a given exit. I also loathe that Allstays has no WP apps. It seems like these would be good apps that would do well in a WP store if someone wanted to develop a version of them for WP. Most of the data is available publicly. The Streets & Trips Mega POI file has most of the detail available.