We've done three such cross-country trips of over 30 days each. You didn't say if you had kids with you but if that is the case, I'd break up a 1900-mile trip like that in half with a day or two off the road, or possibly a driving marathon to the Outer Banks but then making time to stop & see things on the way back. Just saying'.
I would book the campgrounds for the first half of the trip, especially if we were in a popular tourist area or if we needed to have a site over a holiday weekend. I'd have already planned out where I though we'd be staying for the balance of the trip and would call those campgrounds a day or two in advance to reserve. We had a couple of instances where the places I anticipated we'd stay did not pan out, and in both cases we ultimately lucked out. It's no fun not having a place to stay in hot, humid summer weather so advance planning can really save the day.
Figure closer to 50-55 mph for your rate of travel. Enjoy & safe travels.