You should be ok with 80/76/70 going down. We were at Cherry Hill last year. It was a nice cg, but being so close to major highways, it was a little noisy. If you can, make Old Town Alexandria a part of your trip.
Don't worry about 95. There's not a road in that area that isn't a mess, so it can't be avoided.
Williamsburg is nice, we went ther 2 years ago, including Mt. Vernon.
If you shoot up 64 on the way back, don't miss.Monticello. Jefferson was amazing! We took our TT down 81, stopping in Luray and Monticello on the way to Williamsburg and had no problems.
Another alternative for the way back, depending on how much time you have, is to go up 15 and visit Gettysburg. Now That's worth the trip!
