If you bring the .280, you'll be in good shape. If you bring the .308, you'll be in good shape. Be sure your rifle is equipped with a low power fixed or variable power scope, preferably one with a reticle that is visible against a dark background in subdued light. The rifle that ensures quick handling, that you can shoot well from 25 out to 300 yards, is the one you want if still hunting. NL-Hunter's suggestion of taking both rifles has merit.
As for bullet choice, honesty compels me to say that rail cars full of moose have succumbed to factory ammo loaded with simple cup and core bullets, fired from rifles chambered for moderate cartridges like the .280 and the .308. If that suits you, then Hornady Interlocks are as good as anything. But if the choice of a high quality bullet gives you a warm comforting feeling, the .284/160 gr and .308/180 gr Partitions and Accubonds are proven performers.