I was there a few weeks back, where I met Bob McGrath. Live cast members do show up every now and again.
Sesame Place is actually a pretty small park, but there's something for everybody. They have mostly kiddie rides, but there are a few grown-up rides and water slides too.
They also have a replica of the street, with Hooper's Store, the "Arbor Area" (where for years they had the garage with the NO PARKING sign, and the green staircase), the 123 brownstone building (complete with stoop), Oscar's garbage can, and Big Bird's nest area. Great for taking pictures. Bert and Ernie hang out there a lot.
They have plenty of walkaround characters, so it's easy to get a photo op with them. Bert and Ernie, Big Bird (who for some reason wears a necktie), Grover, Cookie, Telly, Elmo, Zoe, Baby Bear, Rosita, and the Count are pretty easy to spot and love posing for pictures with you.
Twice a day they have a parade down the street which is quite an event.
If anyone ever comes out to the East Coast, Sesame place is worth checking out.