Call me old-fashioned. . . but I really really love maps. I don't leave home without them.
A Triple-A (AAA) membership will cost about $50 per year and with that you get emergency roadside service (gas, change flats, towing - but perhaps not motorhomes or travel trailers) all the maps you could possibly want for just about every state, city, town and geographic area in the United States plus camping books, tour books (which show attractions), trip planning, discounts at campgrounds, discounts at various attractions and etc. The maps and tour books are included as part of the membership at no extra charge.
I also buy U. S. Forest Service maps for the areas that I am visiting volcanoes in. These are quite detailed and show the unpaved, but maintained, roads in Forest Service areas.
Anne