As far as what are you wanting to know.
State parks u can metal detect on most of the beaches but with a no cost to you permit. As far as detecting in a state park no.
Sorry not sure if thats what you are asking about.
I`f you want to get a permit you can get it through I believe dept of conservation on the web. took me a little while to find it but you can do it e-mail and they mail it to you no cost but it only states for beach areas and you have to find the list of which one`s it is.
Diving ?
Every lake is different you will have to find out were they allow diving and what restrictions they have for safety water patrol here is a buger and don't mess around.They have no problems writing citations.
There is some really great places there to go,alot of old homes but if you don't know anyone there maybe get things set up first trip so ya got somewhere to go on second trip.
Sorry to far south for me but main thing is if you going to do lake-beach detecting you will need the permit.
Public parks I would just call but we detect in all the public parks in a 60 mile area in central Mo. {ie unless posted}
Most of the phone # you can get on line would be my guess a few quick phone calls to branson parks and rec dept and where ever else you are want ing to go would get ya ready to come play in Missouri.
Anyway i`ll quit rambling and hope this helps