Thanks to all who provided suggestions. Some were incorporated. Some were not, either because they didn't fit our plans, or couldn't fit into the schedule. But it was a great trip. Our basic itinerary was:
Day 1:
Traveled all day and got into Dulles early evening. Traveled to our hotel in Arlington, walked around a bit, got dinner, and called it a night. The awesome thing was that there was a metro station in the basement of our hotel, so we could get to downtown VERY easily.
Day 2:
-International Spy Museum
-Took in a lot of sights around the national mall
-Ford's Theater
-"D.C. at Dusk" bus tour (hopped off the bus at various locations)
Day 3:
-Slept in a bit, since the prior day was VERY long, and we weren't fully adjusted yet.
-Took in a couple of Smithsonians and more sights along the national mall. Made a point to hit the Capitol and Supreme Court.
Day 4:
-Mt. Vernon
-Old Alexandria
-USMC memorial
Day 5:
-After church and a long lunch with an old friend who is working at the Pentagon, we drove to Harper's Ferry, which was not planned in advance, and ended up being an unexpected highlight.
Day 6:
-Drove to and visited Monticello, and then on to the new hotel in Williamsburg
Day 7:
-Historic Jamestowne
-Colonial Williamsburg
Day 8:
-Busch Gargens, Williamsburg--just wanted the kids to have a chance to blow off some steam before coming home and not have the whole trip feel completely like a week of school.
Great trip. Great memories. And lots of great food, including introducing the kids to Ethiopian food, and them loving it so much that we had to go back a second time. A few pics:
Downtown D.C.:
("Look, is that Spiderman?" became a tired running joke the whole trip every time the Washington Monument was in view)
Capitol view at night:
Mt. Vernon:
Monticello:
Harper's Ferry:
USMC:
...and an ACTUAL Enigma Machine!
(yes, I texted a pic of this to JP!)