If dh is a pilot, he will love the new Air and Space Museum near Dulles airport - it is fantastic. And the kids will love climbing on planes, etc...
Also, the Skyline drive is good fun and different if the kids do not mind the car for a while. The views are fantastic and you get to see all sorts of wildlife - even bears if you are lucky.
Monticello, near Charlottesville, is fantastic, much nicer than most of the historical recreation places - details here. But the kids will probably really enjoy Williamsburg.
TBH, my ds, who I take to visit grandparents in Virginia about 3x a year, is just happy to see different things from his usual sights. But when we drove to North Carolina last year (Wrightsville Beach, just down the coast from where you are going), we did have a portable DVD player in the car, because distances are so big.
If you keep an eye out, you will come across civil war battlefields every so often - Appomatox, Richmond, etc... - which are fab places to stop and stretch legs and run around. You will usually find picnic tables, possibly toilets and also good parking. And there will often be a visitor centre as well.
The Aquarium at Virginia Beach is great for kids.
Actually, I find it easier if I plan for an indoor activity around the middle of the day, as it is often too hot to be outside - you need that air con. You will usually find a play area in a mall, often near the food zone - very useful as it will be cooler and you can take a break.
You will find plenty of things to do in Wilmington and the big battleship is a great day out for kids. Also, the boat tours are fun. But the best thing about the area is the beaches - they are fantastic, with great sand and shells. Take a kite!
Sorry, a bit longer than I had planned, but it is our favourite holiday place. Let me know if you need more info.