From my experience at the pool last weekend I can tell you that the lazy river does close at 5. We checked in right about 3 and stayed in the lazy river for almost two hours before it closed. The pool area at Ron Jon's is massive! They have a water playground for the kids. A big waterslide, the lazy river, a huge swimming pool and several jacuzzi's.
I have only seen pictures of Radisson's pool which looks very very nice, but I think Ron Jon's probably has them beat with the lazy river and all.