6.7 or 7.3 in Alaska

I am looking to make my first super duty purchase. I am planning on moving back to my home state of Alaska and I want to have the truck for living there. I see a lot of debate on 6.7 powerstroke or the 7.3 gasser and I haven’t found one that fits my specifications. I work from home so I won’t be doing commuting, I plan on using the truck for normal truck chores but I would really like to tow a 5th wheel toy hauler that’s large enough for the family and a 4 seater SxS, maybe more. With the Alaskan terrain and weather, which makes the most sense? I am buying used and plan on looking into DEF delete if going the diesel route. Whichever truck I buy, I intent to ride it till the wheels fall off so longevity is important.