maps.com provides printable maps, driving directions, address finding and has a large reference section.
Rand McNally provides driving directions, road construction maps, airport maps, travel tips and lots of help planning your road trip. Their On the Road with Kids sections gives lots of ideas for kid-oriented travel. Plus there are lots of ideas on how you can Explore America.
The U.S. Department of Transportation, Federal Highway Administration has a good site called National Traffic and Road Closure Information. This site has a map of the U.S. and you can click on the state you want information on and from there you go directly to that states DOT page with listings of road conditions, construction areas and more. Also listed is the new Federal Highway 511 program and the states that have this service. Plus you will find lots of other helpful information.
And for fun – check out the web site for the National Scenic Byways Program.
And if you are looking for a good place to eat along the way roadfood.com is a site “devoted exclusively to finding the most memorable local eateries along the highways and back roads of America.”
If you are interested in outdoor recreation then you must visit recreation.gov. The clickable U.S. state map on this site will take you to links for various recreation activities (biking, water sports, auto touring, and lots more), state tourism sites, National Recreation Trails, maps, and weather advisories from weather.gov, NOAA’s National Weather Service site.