THEORETICALLY it sounds like a great idea. REALISTICALLY you will have much competition. Kingsport already has 2 Wal-Marts that sell fishing and hunting supplies and Jon boats; there's M&M Sporting Goods that sells fishing, hunting, and archery supplies as well as ATVs; there's Green Spring Marine that sells several different brands of boats. In the outlying areas there are many Bait and Tackle Shops.
I really don't want to discourage you but you may want to take a look at something totally different.
May you prosper in whatever you do.