Any Pro-Am circuit is going to cost a bit. If cost is an issue it may not be the best path. If it is not, then you can learn quite a bit from the boaters, problem is, like mentioned, all "pro" means is they have the money to spend to be a boater.
another option is to try to find someone to hook up with to fish smaller derbies on the lakes you want to fish. I know table rock has quite a few weekly tourneys during the year as does Pomme, LOZ etc. These many times are pretty low cost. Pomme has tourneys like BATS and Pomme Bassin Nights that are about $50-$60 a boat.