Jim,
As a long distance member of the seashore Trolley Museum do check in for a weekday visit. They are the oldest streetcar museum of all! And a place to ride open streetcars;
which are pretty rare even among streetcar museums!
Something that has not been mentioned if you like lighthouses is the Maine Lighthouse Museum in Rockland, the Lobster capital of the world. Also, in Portland is the Portland Observatory which used to announce arriving sailing ships, before the electric telegraph. You can see a bunch of lighthouses from up on top. The Maine Maritime Museum in Bath has a Fresnel Lens on display.
if you have to visit the WW&F Railway Museum on a non-steam day ask them to take you for a ride in the model T rail car; it is a sweet ride.
Maine is a great place in the summer time!
Also remember that these places also have Facebook pages.
Ted Miles, WW&F Railway Museum Life Member