Another what gun?

Also, keep a trigger lock on your rifle while traveling. Game Warden will check you if you are on the road. They seemed pretty strict about it.
Yeah when I went Canada on a bear hunt I was told by guide better have trigger lock on when go across border
My personal choice would probably be 30-06 .The flat shooting cartidge is useful and has plenty of knockdown power. caribou are generally weak animals but they typically live in wide open country and can travel very far with a poorly placed shot. I would recommend shooting sticks or a bipod as sometimes hunting caribou you can’t get within 250 yards due to terrain.
30-06 would be my selection of the 2. Better glass and a tad more energy. Not saying the 7mm-08 wouldn't do the trick, I'd just take the best glass with the most energy I could get on such an important hunt.
Either will do just fine in terms of killing power, I'm amazed at those that underestimate how capable the 7/08 is....zeesh

Bou are not difficult customers to take out, if I was going Bou only I'd have zero issues taking my 22/250!

I'd take the rifle I shot the best, and if it was the 7/08 then I'd merely switch the glass on the two guns.

Far as the concept of buying a new rifle for a trip out of town, let alone country there's zero chance I'd do that !
I have hunted Caribou 2 times in Quebec, Delay River 1 trip. Hunting migration trails mostly. Hide behind a rock or spruce tree and shot them at 20 yds. with a bow. 7 of 11 Caribou killed in camp were Bow Kills.

I have hunted Newfoundland 2 times. Hunted Moose. But seen a lot of Caribou, They seem to stay on high ridges. Seen a lot near Buchans on a hunt there. Caribou season was next week. Seen caribou from 50 yards to 1000 yds. All moose we seen was long range, 800 yds. and beyond. The weather was warm Bulls would not answer calls. South of Red Indian Lake seen moose no bulls, Brother and I had Bull/ Calf tags. All areas we hunted in Newfoundland had many places my 550 yard range finder was useless.

Take the 30-06 and may wish you had more rifle when it comes shooting time.

If you are driving, Be sure to get Ferry Reservations in advance, And plan time in your drive to arrive early. I suggest book a 11:00 pm ferry crossing. Get a room sleep on the ferry, Be ready to drive in the morning. Going and on return trip too. Be sure to set up a GPS and put the coordinates of the gate at the Sidney terminal in. My GPS took us right to the gate. Bon Voyage