Today's archery equipment has become so advanced that just about any setup will get the job done on an Alaska caribou bowhunt. The state requires a minimum of 40 pounds draw weight and a broadhead that has a cutting diameter of at least 7/8 inch.
Bow
Flat-shooting, short axel-to-axel bows work great whether on the open tundra or stalking one of the many willow-choked rivers. Being able to shoot longer distances are a must. Tough-built bows that are forgiving and fit you well will be a big plus.
Broadheads
There are hundreds to choose from, but remember not all are created equal. Caribou are not particularly tough to kill, but you will need good penetration. Choose a head that flies like a field point and does well in the wind.
Arrows
I take a dozen. They, too, must be durable and fly well out of your setup.
Multiple Releases, Optics, Case
Take two releases, the best binoculars you can afford, and a reliable rangefinder. Spotting scopes are good, but not necessary. Also if you can find room, bring a soft bow case to put it all in. Bush planes are small and big cases get left at the airport, but a soft case will protect your gear somewhat when it's shoved into the Super Cub.
Extra Socks
There is nothing like putting on a dry pair of socks at the end of a hard day of hunting. I recommend wool or synthetic with a lot of cushion for your feet.
Tarp
Rain is a fact of life during Alaska's fall seasons. Personally I like to have a fire at the end of each day. After gathering firewood (as much as possible), cover it with a tarp to keep it dry.
Quality Rain Gear
Keeping dry and comfortable is the key to an enjoyable hunt. The long days in September will allow you to hunt 14 to 15 hours a day, and rain is pretty much a guarantee. Personally I use the Sitka line, but Cabela's Dry-Plus is also a good choice.
Knee-High Rubber Boots
Bulky, heavy waders are not required for chasing caribou, as caribou are usually found on the tundra. Most times a good pair of knee-high rubber boots that have great soles and good insulation will work fine. I personally wear a boot that has 2,000 grams of insulation and tremendous ankle support.
Quality Game Bags
Not all game bags are equal. Quality bags will not only save you a lot of time, but keep your meat in better shape and your transporter in a better mood.
Satellite Phone
Last, but certainly not least, rent or buy a satellite phone. They can and will save your life, especially if something goes wrong and you're hundreds of miles from help.