Well, if you carry the Mora on your belt, it doesn't count as pack weight...
I always take a fixed blade with me, but your Gerber should be all you need for trout. I never fillet trout less than 5lbs, and I doubt you'll run into any of those. Gut them with your gerber, stuff belly with seasonings, butter, etc. wrap in foil, and cook. That's how I've been doing it since before I have memories. Just be careful of the bones. If you've never eaten trout, you don't need to worry about scales either.
You can have fires on the John Muir under 9,000ft, right? If that's the case, leave the pan at home, take some foil instead and throw that bad boy in the coals. Take 6oz of whiskey instead. Sip and enjoy around the fire while your trout cooks ;)