The park is located closer to New London than Hannibal but it is an easy drive to tour the sights in Mark Twain's home town. We stopped in the winter (Nov) and there wasn't anyone in the office. There is a number posted on the door that you can call to find out how much to put in the envelope. They offer a GS discount. The sites are large enough for a 45' MH but parking the towed could be a problem with some of the spots. I didn't see any concrete pads but all the sites seemed somewhat level.
The best thing about this park is the price. There are not too many places where you can get full hookups with 50 amp for $12 a night. It is certainly not a destination campground. It's a place to park for the night or if you want to see the area or are passing through. Don't bother with Wally's the Boomland restaurant. The cafeteria style place is clean but the food is privy and overcooked and the staff is not very friendly. They advertise inexpensive fuel but they are about .15 a gal more for diesel than the surrounding area. If you are in the market for fireworks this is the place to be. They are very inexpensive.