Bring your wall chargers. When you eat out (cafes, fast-food, whatever), bring your e-stuff and chargers in with you, and select a table next to an outlet. Plug in while you eat. Same strategy for libraries / internet cafes / laundromats, etc.
If you stay in RV parks, many have rec-rooms or laundry rooms or something like that, where there is an outlet. Worst comes to worst, if you are in any sort of campground, there is usually an outlet in the bathroom (althoug it sucks hanging around in there until the thing is charged.)
Don't leave your electronics alone while charging.
Turn your phone off most of the time.
To plan places to stay, first of all, your AC maps have lots of info. Also, almost every town of any size has a chamber of commerce or tourist info center. They have brochures for camping. The people who work there are usually knowledgable & friendly. Just ask.
Also, RV parks are OK, they are usually expensive but have good services (laundry, pool, ice cream). Many tourist info centers and almost all RV parks have brochures for RV park chains, and/or for the state.
Forest Service, National Park and Bureau of Land Management Ranger stations have lists/maps of low-cost camp grounds. State parks will often have info about other state parks in the area.
If worst comes to worst, go to the police/fire station/library and ask if they know anywhere you can camp for free (park, fairground,etc.) Also, don't forget kindness of strangers - ask for help and someone will.
AAA Maps and Campbooks have a lot of info too, often redundant with the above sources.
Usually every night in my tent, I look at the map for the next part of the route, look at my camping resources, and pick a couple of probable destinations, one short/moderate distance, and one optimistic/long distance. I only reserve in advance if there is a holiday or other reason to think it will be hard to get a spot.
And don't rule out the hotel every week or two - it can really help if you are sick, or freezing, or whatever.
Have a great ride!!!!
Anna