Welcome! You are going to have a great visit!
I would quibble a bit with your choice of a Tundra unless you bought an extremely small fifth wheel camper, but I would defer to the opinions of others.
Some suggestions:
-- The great National Parks are a given.
-- Washington, DC, my hometown, has a lot more going for it than many realize, from museums, to restaurants, to historic sites. And the attractions continue all through Virginia. The secret to Washington is to use the Metro and to visit either before school lets out or after it returns. The cherry blossoms are lovely in the Spring and the Indian Summer in the Fall can be amazingly warm and comfortable. (The less said about July and August, the better!) The Fall colors on the Skyline Drive and elsewhere in the state are beautiful.
-- Don't miss Mount Vernon and at Mount Vernon, be sure to drive the extra mile or two to visit the mill and distillery. (Sadly, they don't offer tasting and the bottles are over $150 each.)
-- Gettysburg is a moving site. Allow at least one full day to visit the battle field and spare an afternoon for downtown. Historians will tell you to visit in July, so you can appreciate the weather at the time of the battle, but you will be more comfortable earlier or later in the year.
-- Off the beaten path, the Jack Daniels distillery, and indeed, the entire whisky trail is fun.