Places...Lake Tahoe is wonderful just about any time of year..except spring, as the snow melts the roads just get bad..
San Francisco is nice and is worth seeing just for the views.. (and it's where Starfleet Command will be based about 200 years or so from now)
L.A. As seen on TV!! and Disneyland is nearby...stay on the tourist routes and you'll be OK..
Fort Worth Texas..if one wishes to see a subset of American culture..you can right there...as long as you stay out of the area called Como..you should be safe..
Of course Orlando..is nice but totally a tourist based economy..
New York...it's got everything..just about every culture in America can be found there..(even Texan)...
For Nature lovers...Yosemite, and Yellowstone..(except in Winter..it's just too cold in those areas) ..
Beach life...Malibu, Miami, ....
Desert Southwest...Grand Canyon, your also cose to the California High desert...
Now to take it all in...Interstate 40 covers some of the South, Central Plains, Texas, and the Desert Southwest and in areas closely follows the old Route 66.
http://en.wikipedia.org/wiki/Interstate_40
http://en.wikipedia.org/wiki/U.S._Route_66
Or a run along the old Lincoln Hwy is recommended.. you can see a LOT of America from this old route..
http://en.wikipedia.org/wiki/Lincoln_Highway
You are quite safe along those routes..and with GPS systems cheaply available, it's hard to get lost...