I grew up in that area and know it well. Reservations are a MUST. Okoboji is a very popular area and sites fill up quickly in season. There is a lot to do in the area - many family friendly. A highlight of any trip to Okoboji is Arnolds Park, a ride on the Queen boat and the free concerts on Saturday nights. There is a private RV park closer to the heart of the action (I've heard it can get a bit rowdy) but I prefer the State Parks that are a little further out. All state parks sit next to a lake. Hope that helps!