Michigan to Washington DC / Colonial Williamsburg

You might want to see my post on another thread on this forum (Jacksonville FL to Allentown PA)

I would certainly concur with the suggestion about Gettysburg and add that a visit to Lancaster, PA (area) and the Amish country--if you have not been there before.

I edit to add that I agree most heartily with the suggestion about Montecello. We had a delightful visit there a year ago. We stayed out at the Misty Mountain RV Park which I do recommend.