Just a thought, im a supporting member with several like forums, and have been for m any years, the recommended "support" of these forums is nowhere close to what you're asking, a lot of people are up and aged or on fixed incomes. Also, the marketplace section, advantage/disadvantages by membership price, this is definitely not the way to go, most items that are worth buying are gone in minutes. This drives people toward a platinum membership which i believe most will be unwilling to pay, i would definitely reshape things to what people are used to. I believe you'll see better growth.
I believe a Michigan sportsman forum could be a great if it were structured properly, the marketplace on most forms is a great attraction. I don't believe people will be willing to pay the price on your's, just a few of my thoughts about this, I wish you the best....Mark