HW,
I am assuming you are a non-resident to Alaska. First start with the AK hunting regs which you can find online easy enough, the start going through the Game Management Units (GMU) that allow for non resident registration hunts and or regular hunts that require just a harvest tag.
Once you have a general area you want to go then you can start researching the outfitters / pilots in that area.
The other option besides a drop camp caribou hunt would be a float trip hunt. These are quite common, you would get dropped off on a river such as the Colville River and float from Point A to Point B over a certain number of days. At that point you would be picked up and flown back. There are numerous outfitters out there that can help coordinate both rafts, gear, and transportation. The benefit is you get to see a lot more country, more animals ( bear, moose, wolves, caribou, ....), and some fishing.
Most outfitters are going to be straight and true. With the power of social media these days most outfitters are going to be wanting to put you in a good place so you have a good chance at a successful hunt, that way they can keep a good reputation and clients. Just make sure you do a little homework on the outfitter with talking to references and possibly with Alaska Fish & Game.
Good Luck,
Mike
