Fantastic place for kids! Especially for young boys who love trains, like my two.
If you go for the "free stuff" like the playgrounds and the park, you won't be disappointed because what's also free is the model train museum that's been recently rebuilt (and developing every week as the create the new layouts). Such a nice place for a weekend get-out-of-the-house thing to do.
Of the paid stuff, the train rides are great, as is the carousel for this little ones. Check the hours though--not always running so you don't want to disappoint the kids if they see it and it's not open.
Hartleys is great for ice cream or a float and the toddlers can play at the Thomas Wooden train table while they lick.
If you like history, check out the Pullman car, used by FDR himself back in the day. Good stuff!
LOVE, LOVE, LOVE this place!