Apps to find campsites along routes

I'm tentatively planning to do as much of the Rail's to Trail's route from Seattle to Washington DC, as I can manage. Starting slow and doing Seattle to Snoqualmie Pass for a couple of trips, then to the Idaho border, etc.

The problem I've been coming across is how to plan routes from one campsite to another a reasonable distance away. Most navigation apps that are good for finding nice biking trails, seem poor for finding campsites along the way. Juggling 10 apps while on a trip seems like no fun, and planning out each leg of the trip in painstaking detail ahead of time also seems no fun. I'd like to have the flexibility to plan the route as I go.

Any advice on apps/websites that work well as a one stop shop for finding bike friendly campsites, along with navigating the best trails? Bonus points for apps that allow you to book online, and list ammenities like electricity, showers, etc.