This is less specific advice than you might want, but I have lots of experience setting routes for car rallies using maps. I try to look for interesting drives, which often coincide with interesting places to photograph. Other than relatively expensive (and too numerous) 1:50,000 scale topo maps, if you can get a hold of some region maps of 1:250,000 scale that show regional and county roads, use the ones that curve a lot. When they veer away from the straight grid, it's usually because of hills, parks or valleys. If you're taking a roundabout route, may as well increase your odds.