I am the trip planner/navigator. I use Benchmark atlases of individual states plus their fold out maps for an overview of the state. I also have a few deLormes and the detailed maps of specific areas/national parks published by National Geographic. I have Laurent Martres books on photographing the US West, rockhounding series for individual states and several off road guides like Tony Huegel, Charles Wells and the excellent series by Peter Massey, Jeanne Wilson and Angela Titus. We usually decide how long we will be gone, what areas we want to see that we haven't before and which ones enroute that we want to revisit.
I plan a route avoiding interstates and big cities (we get enough of that living north of Seattle). Then, I connect the dots of the big POIs and destinations and look at maps and books for those in the vicinity or along the way. We have at least 4 trips for this year and it is fun to choose where we will go. I like Benchmark for its geographic labeling to find interesting places to photograph.
I bring the maps and some of the books but make copies of info from some of the books which we won't use as much. We don't always follow our plans. The government closure last fall had us eliminating Yosemite and Mono Lake in favor of eastern Sierra canyons and lakes.
Have fun.