Dave,
Get a nice big atlas, the kind that devotes one or two pages to every state, and that notes places of interest on the maps. I have one from Costco that was about $12 or $15 and also list events and festivals by state at the back.
Look in the direction you want to head to from where you are (as korbe noted, south for the winter, north for summer) and take a good look at the map for all the interesting spots and take off. I guarantee you will be weaving all over but if you don't have to be somewhere, what difference does it make? Stop at all states' visitor centers and look at what's on offer. Many towns and counties have the same thing and you'll be amazed at how much there is to see. Go online to the communities you're heading toward and see what they promote.
I've been on the road for 13 months now, granted most of them volunteering at national parks, but can assure you there is not time enough in this life to see all I want to see.
Happy trails and safe travels!
Kathy
Fulltiming until I have seen everything I want to see, it isn't fun anymore, or I run out of money. Let's hope it's not the last one.
Cruisingat60 blog.