Not sure how much the outfitter told you.
Snow is a definite possibility. So are fairly hot temps. Maybe bring a packable fishing rod depending on location.
Most of the country is fairly thick. And steep. I would pick an "all-around" kind of rifle. LR rigs might get a little heavy if you're not using horses all of the time. Griz all over the place. Not as mean as Yellowstone area bears though.
Should be a fun hunt. Where are you going in from?