It's more than enough power to go over the mountains. It likely won't be the fastest vehicle to do so, but you'll get over them. Likely a Ford chassis with half again more power would accelerate a little more quickly and may still be a bit faster driving in the mountains (even with the greater power loss due to not being turbocharged), but you'll still get where you're going and in reasonable time. Once you arrive, any engine power difference makes no difference at all in the campsite.
I have yet to hear anyone who believes their motorhome is overpowered, for what that's worth. You'll never accelerate like a car, even a "slow" car (which I guess these days means all of 9 seconds go go from 0 to 60).