I'm headed to Adak, AK for a long job.  I'll be doing several Caribou hunts, and some birds while I'm there.

The long job part is important, because I'll be very limited on what I get to bring with me.  6 Months of work and weather gear, personal supplies, laptop, etc.  So, I want to take the necessities to cover several areas of needs; living, working, hunting, and fishing.  All of this needs to basically fit inside of a 150lb limit.  Fortunately, the boots and wet weather gear are needed for work, so that's 2 birds with one stone. Some supplies are available on the island, and I can always mail order things too.  But there is a huge premium paid on shipping.

My thoughts,
super light pack frame and bag (what one, I don't know), that will also qualify as one piece of luggage
Havalon knife w/blades
game bags
.270 and ammo
12ga also, for the Ptarmigan
550 cord


So, if you were day hunting for medium sized game, what would you absolutely not go without?

Binos and a big pistol would certainly be on my list.

Do not skimp on good rain gear

The rain gear will be a must for work, so I will have plenty available.  6 months of cold, wet, and very windy.

Binos vs good range finder?  I was just planning on using a range finder, do you think both would be necessary?  The island is tree-less, and has about 3000 Caribou by last survey.  I'm thinking it's going to be almost to easy to find a herd.

And as far as the pistol goes, I'm not sure yet, as there are no predators on the island, besides eagles, and I will not be shooting one of those.  No bear, wolves, yotes, or anything else that should be attacking me, maybe a pissed off caribou, but that would be way out of norm.

I'd rather have binos than a range finder, but to each their own.  

Also, I thought the bears up that way can swim, like a long ways?  

Seriously, sounds like a hell of an opportunity,  Take the gear that makes YOU the most comfortable while hunting and enjoy it!

Not sure how far the bears swim, but the island is close to 1000 miles from the main land.  

Agreed on what makes me the most comfortable.  I just have limited hunting experience, and this is going to be a LONG trip to not realize I needed something vital. For example, I plan to not take a saw, I'll do the extra work with a knife instead.

Ask in the Alaska HTF.

Just remember light = expensive

Only bring two knives one fixed one folder/pocket.  Don't be that dude who brings 6 knives or what ever.

Make a list of what you will need.  Then pair that list down to essentials.  

I like good stuff, and would be able to pay for it, but I am really going for the minimalist approach.  I've seen people take 2 saws, a canvas, ropes and pulleys, several knives, plastic bags, gloves, lights, etc etc.  I'll have to pack the meat out on foot, and that should be 150-200ish.  So several trips over rough terrain.  Hopefully only 1-2 miles or so miles each way. If i'm carrying everything plus the kitchen sink, I'll just be adding extra trips.

Below is the checklist I put together for my Elk hunt last fall.  I was camping in the forest for several days, so slightly different requirements, but this list may help you think of something.
Camp Gear
First aid kit (including Pressure Bandage,Bandages and Triple Antiboitic)
Water purification filter
Water purification tablets
2 Flashlights with extra batteries
2 Knives
Wet stone/knife sharpener
Folding saw capable of cutting bone
Canteen Cups
Camelbak
8 10' sections of 550 Paracord
Tent
20 deg sleeping bag
Foam sleeping pad
Waterproof bags
Pillowcase (stuff extra clothes in the case at night)
Waterproof matches
Lighter
Tinder material
Toilet paper
Baby Wipes
Camera
Sunscreen
Insect repellent
4-5 Game bags
Trash Bags
Fishing Supplies (optional)
Utensils
Cooking stove+ fuel
Hand/dish soap/shampoo
Outdoor shower
Pack frame
Bungle Cord
HUNTING GEAR
Small daypack
Compass
Altimeter or GPS
Bright tape to mark trails
Muzzleloader + sling + case
Bullets, Powder, primer
Cleaning equipment for muzzleloader
Tags/licenses/hunter education certificate
Binoculars
Rangefinder
Maps
FOOD
Instant hot cereal
Instant coffee
Hot Coco
Trail snacks (jerky, dried fruit, Granola)
Summer sausage (great for lunch and it lasts several days without refrigeration)
Macaroni and cheese
Powdered milk (use for Mac & cheese)
Dehydrated dinner meals
Salt/pepper packets
Add bacon, pork and beans, eggs, fresh fruit, etc., as long as you can pack it in
CLOTHING
Rain gear
Thermal underwear
Fleece
Extra socks
Extra gloves
Warm stocking hat
Brimmed hat for hunting
Camouflage
Blaze Orange Vest
Blaze Orange Hat
Spare Glasses
Tooth Brush/Paste/Floss
Satelite Phone/Battery
FOR THE RIDE HOME
Large coolers for game (foam coolers are perfect)
Dry ice
Power Inverter
Clean clothes

My thoughts are forget Havalon and take a good folder and one fixed blade hunting knife.
I would consider 30-06 instead of .270 only because I've seen 30-06 at a lot more places than .270.

Also, I'd take good 8X or maybe 10X bino over range finder.
Long wool scarfs, fur hat and good waterproof gloves will go long ways to keeping you warm.    

I believe caribus are about 170 lb. which means you'll have about 65 lb. of meat to carry out.