Since your other posting indicates you're doing something like a PCS move from one coast to the other you might want to bound the question a bit more with kinds of interests and amount of time available for stops.
Some folks are retired RV'ers who have 6 months at a time to spend on a trip and have varying interests in destinations.
Others, like me, don't have that kind of time and aren't even sightseeing - just planning an efficient route and figuring out where to stop for food/gas/lodging on the way.
I use Google Maps and Google StreetView a LOT to examine terrain and density of restaurants and lodging along the way.
I also use radioreference.com for info to program my radio scanner for all the states/counties/towns/state patrol/snowplows/airports along the way so I can hear of road problems (like crashes and road closures) and local amusements (hearing Spokane police dispatched to a home invasion where the intruder was "given a temporary loss of consciousness").