I don't think any single app is going to do this for you.
What I do is look on MapQuest for the route, then note the closest town to where I'm likely to want to stop. Finally, I use the android app RVPARKY to find rest stops, walmarts, campgrounds, and fuel stops near those towns. Ultimately, though, some days I can go further than others, so I use RVPARKY almost continuously to see what looks good up ahead.
2014 Coachmen Catalina 253RKS
2016 Summerland Mini 1750 RD
2012 F250 Lariat FX4 Crew Cab 6.2L