Most all of us use one of two guides: Trailer Life's Campground Directory or Woodall's Campground Directory East/West. They rate commercial campgrounds in terms of amenties, physical facilities, and santitation. The also list last years prices, site size, and directions to them. They give unrated descriptions for public campgrounds also. True gems for RV camping. Used in conjunction with a cell phone they answer most problems in locating decent sites. Should be available thru Amazon.
Browse the forum for tips and lists. Check out our library.
One hint that I have seen nowhere, but a foreign visitor might not know is to buy one or two $10 rolls of quarters (25 cent pieces) at a bank when you arrive. The quarter is the universally useful US coin. (We have no dollar coins in circulation.) One needs them for parking meters, laundy machines, pay showers, vending machines, etc. We habitually keep a small sack of them in the trailer.
If you like meeting folks, bring a small Union Jack and display it at your campsite.
If you are in a small town, make a point to have a dinner at a local restaurant. Most CG hosts can direct you to the town dining out spot. Avoid the food at travel plazas. Ours is no better than yours -- cheaper but no better.
I will tell you a secret. Mexican food is basically bland. (Bar tamales, chorizos, and albondigas soup) What makes it spicy lurks in those bowls of evil looking red, yellow, and green salsa on the table. On the other hand, if you are into Indian food, ignore this and lather the stuff on your taco.
If you get to Navajo land, the best buys are their silver work. Pottery is best by the Hopi and Pueblos.
Blue grass festivals are fun. If you can find one, go. You are liable to recognize a lot of the tunes -- they are British in origin. (see skiffle).
Give a lot of time to the desert southwest if you can. Do a loop around the canyon country: Zion NP, Capitol Reef NP, Arches and Canyonlands NP, Monument Valley Tribal Park, and the incomparable Grand Canyon NP. Pick one, pick all. Each one is worth a detour and each one is almos unique in the world. The forum has a rally at Arches in the latter part of May -- see the Moab topics on the forum.