Martin, I am a maphead, and don’t have or use a GPS or Smartphone.
For a map/atlas I am a huge fan of the DeLorme Atlas and Gazetteer for whatever States I will be visiting, or even passing through. That is a pricy solution (I have probably collected 30+ States at this point), but they are worth every penny in the long run.
https://buy.garmin.com/en-US/US/p/575993
I’d at least get those for the States where you plan to spend much time. Just a side note: a stack of Atlas and Gazetteers fits nicely in a Xerox paper box lid.
For a paper guidebook identifying inexpensive RV/camping spots you are looking for this:
https://www.amazon.com/Camping-Ameri.../dp/0937877557
12,000 free and low cost campgrounds. That book has both printed directions and GPS coordinates
My favorite camping guide remains a mid-70’s Rand McNally campground atlas that includes all 50 States (and Canadian Provinces). It is nearly 600 pages in large atlas format, but it includes every State Park, State Forest, National Park, National Forest, BLM, City/County/Civic and private campground, with directions, info about # of sites, acres, seasons, fishing, boating, hiking etc, all presented in an easy to survey grid.
It is 45 years out of date, but all of the public stuff is still there. Most helpfully each site is numbered on a State road map, so it is excellent for spur of the moment
let’s stop soon. Just look ahead along our route, find a couple choices nearby and have a read about the specifics.
Guidebook? If you are looking for paddling guides which States are you interested in paddling?
If you settle on a general route I’m sure folks here can suggest “must see” stops.
EDIT: I think the Rand McNally campground atlas is this one.
https://www.ebay.com/i/123780355564...MI_YrWmYXj5QIVr4VaBR3PBQjBEAQYASABEgK8hfD_BwE
The cover on mine has been gone for decades, replaced with some stiff paper and duct tape spine.