@Max re the "industrial hamlet": I bet that is one of those wonderful old factories with a jackshaft running across the ceiling the entire length of the building, with one end protruding out connected to the waterwheel! All of the various machines were powered from this one shaft, connected to it by LEATHER BELTS.., I suspect that's where you developed your fascination with such items.
I should be a bit more specific. By "my neighborhood", I mean it's only about a six hour drive. Probably further than the Rocket center. We do have several other big hydro dams much closer than that.
We've do have a number of very nice avaiation muesums close by. The Spruce Goose is only 45 minutes away from me. The same museum also has a pair of Titan II missiles (one standing inside the building), an SR-71 and an X-15 full-size mock up.
The best mathematics exhibit I've seen is Charles and Ray Eames' Mathematica, sponsored by IBM. Chicago's Museum of Science and Industry used to have a copy of it. It's now at the New York Hall of Science, according to Wikipedia.
Maths is such an abstract subject that i wonder what kind of objects can be placed in the museum to attract crowd. It would be like an art exhibition where you need to loose yourself to understand what a craft and artist is trying to tell you.
I've done the Chief Joseph tour at Wenatchee -- and even cooler, a long time ago I got to stand scarily close to the spillway, since my grandpa worked there (and at many of the other dams, such as Grand Coulee and Bonneville). He also installed lights on the new (not original) Tacoma Narrows bridge -- obviously he wasn't scared of heights!