The western part of the state has most of the mountains and the best scenery. If you are a transportation fan, Roanoke has a great transportation museum and a lot of railroad history. Bedford VA has the National D-Day Memorial. Heading north on I81 takes you into the Shenandoah Valley with lots of Civil War History.
The Piedmont and eastern part of the state offers more history (Appomattox Courthouse National Park), and Williamsburg, Jamestown, Yorktown. The coast offers everything from the ocean at Virginia Beach and numerous places to see the Chesapeake Bay and tributaries. Lots of military things to see in the Norfolk area.
RV parks that can accomodate larger RV's:
Williamsburg......American Hertitage
Virginia Beach/Norfolk.......Holiday Travel Park
Richmond....Americamps in Ashland, VA
There are others but these are three I have used.