We made a longer than normal trip this past summer (not our longest though). Trying to map and plan the trip and came across a website called RVPARKY. They also have an app you can download to your phone.
This trip making app lets you find campgrounds along your route, and even gives height warnings for your projected route. It also lets you see the entire route on one page which is nice for sharing. You can also share the route with friends or relative so they know where you'll be on any given day.
Best part, it's free to use! www.rvparky.com
GasBuddy does a similar thing, also tells you how much it will cost, and where to stop to get the best price on gas.