We did this in Dec of 2003, so my info may be a little dated. Kids were 8,7, and 3 at the time. It was fun. There were maybe 16-18 people total. No characters...just a couple of cast members that I'm guessing are part of the college program. They had songbooks of the old "on top of old smokey" type of songs. Then they organized the kids into a skit. They also read a book. We were surprised that it wasn't a Disney-type book...but Curduroy. anyway, We all had a good time, but we were very ready for it to be over when it was!lol. I would not set my itinerary around this. If you are staying at POR and can make it, then do it, but don't miss something else for this event. BTW, the smores were great...you just buy the kit before you go and it includes a few dowels for roasting the marshmallows, hershey bars, and graham crackers.
enjoy and let me know if you have other questions.