Other things to do :-
1. In Weymouth, try the Rodwell Trail. You walk past the site of a 40mm Bofors gun. Pick up a leaflet at the Tourist centre at the Pavillion which gives details.
2. Nothe Fort. No vehicles, but worth a visit. Several WW2 exhibits.
3. Portland Museum. They have one of the prototype Bouncing Bombs there.
4. If you walk from Greenhill Gardens to the Pavillion in Weymouth, you walk the same route as the American Rangers who took Pont-Du-Hoc on D-Day, when they went to their Landing craft.
Don't know which direction you will be travelling, but if you are near Andover/Salisbury, try stopping at the Museum of Army Flying at Middle Wallop. Food is good there, you see Aircraft flying and you can visit the museum. I tend to stop there for a cup of tea when passing as you don't have to visit the museum to go in the cafe.