This is a recreation of the original Mayflower, and the boat is actually Seaworthy and has been sailed. There are both in-character folks that will tell you what they are doing on the boat, and third-party narrators that will tell you about the history of the Mayflower II as well as the original Mayflower. There are several areas and levels of the boat to explore, including the sleeping quarters, the gun room and the forecastle.
Plymouth Rock is just a short walk down the road. It is fairly unspectacular . . . just a rather small rock with a fence around it that you can stare down at and take a photo of . . . but as long as you're there, you might as well take a look and say that you've seen it! (This was actually one of the funniest parts of our trip. As my four year old peeked down between the rails to see what everyone was staring at, she said "We walked all the way over here to see a WOCK?!" All the folks around us laughed, and one guy said he was thinking the same thing!!)