Inexpensive places to summer over in WI, MI, or MN

This year I’m planning to visit northern WI, MI or MN for a summer of fishing and exploring. What I plan to do is use the RV as a base camp and explore/camp the surrounding area in my Dodge Caravan. When I park the RV it’ll be for at least a month at a time. Last night I began researching the states for a place to park my RV. The folks in northern WI, MI and MN are really proud of their RV parks! Man alive, everywhere I looked they were wanting from $700 to over $1000 for month-long stays. The thing is I don’t need a lake front park, a swimming pool, a recreation hall, I don’t care if it has bathrooms, showers or a laundry, and I have a boat and motor. All I need is a safe quiet place to park my RV and hook up my utilities. I’ve lived in such places in TX, AZ, CA, OR, and WA and they all cost between $300 and $400 a month with full hook-ups. Do places like that exist in the north woods for someone like me?