The terrain may or may not work well for a muzzleloader close shot.
The .06 just might come in handy for a last day longshot.

Back-up it is! No shame in the 30-06, it is the first rifle I've ever owned, that my father bought for me. A beautiful Tikka M65. It has never taken anything other than whitetail.

I could take my Woodsman Hawken, but I've never shot anything other than paper with it.

This is a bare bones trip. Fly in to a base camp, bringing food and supplies. There is a camp "guide", that helps with boats, meat after the kill, directions, etc. Basically, either the Caribou are there, migrating, or there not. If not, they will fly you to them.

I'm allowed 2 caribou. I will diffidently take one, then look for a Trophy! If Need be, I can be more selective with the 30-06.

Only issue will be overall weight, for the fly-In. Hate to have to leave the TP behind!!

If it were me I'd take a Bow, I dont know if you Bow Hunt but that would be my choice. Caribou are some of the dumbest animals on earth, they pretty much stand there and let you shoot them while there looking at you.
If anything I'd take another MLer if a Bow is out of the question, to me there's no glory in taking one with a Rifle.
And dont take this the wrong way.
(BP)

I understand fully.

The group of guys I'm traveling with has had success with a bow on previous trips. I could take a bow, but I haven't shot an arrow since last year.

Muzzleloader is the goal!

I forgot to mention last time, HAVE FUN! and dont hurt yourself dragging out them Caribou.
(BP)

I'm jealous I want to go lol.
I would definitely take a back up rifle and a centerfire to boot. Nothing in the world wrong with that. Like others have said a hunt of a lifetime and anything can happen. Have a safe trip and enjoy your hunt.

Sounds awesome! I would bring a backup gun for sure...

Take the back up.