Apps for gas stations?

Are there any android apps (or even websites) for finding gas stations that are easier to access pulling a fifth wheel? My husband just bought me a 5th wheel to take to dog shows (we're retired and no - he's NOT planning on traveling....) It will be just me, and I'm trying to find ways to plan the easiest routes to places in Western Canada and the North-Western US. I haven't towed anything larger than a 16 ft boat many, many years ago so this is a whole new game. I've got a 2008 Dodge 2500 (gas) and a 2008 28'Cougar 5th wheel.