Mac, do you have local/regional weekly fishing magazines. They would be a great place to check the fall ads for a v20/21.

Salt water is very corrosive to any metals, even marine grade aluminums and stainless steels. Even if you religiously flush and wash after every use, it will still take it's toll after a while. A well cared for used saltwater boat can still be a good one to get, but my point is that since you are living in Michigan, you should be able to find one that has been used in freshwater. It can be worthwhile to travel inland, as BRIANM did, to get one; but not so nifty to do the reverse.

In my area, a boat that has been used only in freshwater commands a higher price, and it's condition can justify it.

Good luck!