The 2nd day of "Kid Weekend" we spent in Strasburg, PA. The two big attractions there (for us, anyway) were the Strasburg Railroad and the Pennsylvania Railroad Museum.
The Strasburg RR has always been a train ride. It's a few miles out and back through Lancaster County farmlands. In summer, you often see the Amish out plowing their fields with their mules, and in late summer, you pass a corn maze (a maize maze?) that you can get off the train and go through. And if you like, you can pack a picnic lunch and get off the train to enjoy that at some picnic tables, then reboard the next train to go back to the station. And for a bit extra, you can enjoy a meal on the train, or ride in an open air car.
But they've added a good deal more there as well. For a little bit extra, you can tour the tower, a couple of restored passenger/business cars, and ride a 2nd, miniature train and manual pump car. With my kids in tow, I didn't do any of the extras, but wouldn't mind doing so at some point, (the pump car, in particular). And for the rail buff, they've got a decent train shop, loaded with railroad books, magazines and such.
Across the street is the Railroad Museum. A few years back, when Son was 3, we had a year's family membership, and got great use out of it. (Hmmm, it might be time to do that again...) The museum has changed a little bit since then, for the better. They've added some newer/better engines in the main hall, and added a great "hands-on" center. I put "hands-on" in quotes, as while they've still got the Thomas tables and push-button layouts, the real fun, the switching station, usually has a line.
The switching station requires more explanation. Along one long wall is a 3-5 foot wide large scale switching layout. Museum folks will present the participant with a problem to be solved: put this car here, and pick up these two. It's exactly the kind of work real live railroaders do daily, and is one of the things I enjoy quite a bit about railroading. (And yes, when the kids have had their turns, they'll let us big kids play, too!)
All in all, both places are great fun, and especially worth the trip for us railfans.