It's a great hunt to do, but expect to walk. The caribou are skittish of ATV's. I did it as a backpacking hunt 2 years ago (South side of island is Wilderness/ no vehicles), and harvested 2 young bulls that were absolutely delicious as far as table fare goes.
It is wet and windy, and the terrain is steeper then what most topo maps would lead you to believe. It gets slick when packing a heavy load, and the soil being volcanic likes to give away under you when sidehilling. A lot of people suggest rubber boots out there, but I used Goretex hiking boots along with Goretex gaitors: they worked great for crossing streams up to about 8" deep, and provided better traction and support.
The store will have most of the supplies that you need, and while more expensive then Anchorage, is cheaper then other remote villages in Alaska. I would recommend taking a white gas backpacking stove, as the store carries Coleman fuel. If you take a canister stove..... good luck!
Take a good spotting scope. I didn't, and wished I had. Folks there are super nice.
I am planning on going back around early October this fall.
