I like the AACA Museum in Hershey, PA. They have a pretty impressive collection, and they have new exhibits two or three times a year. I go up for each new exhibit, so I bought a membership a few years back.

They don't have enough space to display their entire collection, so cars are rotated in and out. The featured exhibits are mostly cars loaned by collectors, with the rest from the museum's collection. They also have a small gallery right off the main lobby that usually features a specific manufacturer, organized by a club.

The Simeone Museum in Philadelphia has a really nice collection of vintage racers in as-raced condition, and displays pretty much all of them all the time.
I can also recommend the Eastern Museum of Motor Racing in PA.

I'm waiting to hear back from another museum in Philadelphia that suspended tours due to COVID.