This is amazing. Thanks for all the input folks. Very interesting.
So what I'm hearing is that, performance wise, a modern gas engine/transmission combo could do the job with a bit of effort in the mountains but diesel wouldn't break a sweat and could cruise comfortably at higher speeds. Also, a DRW is preferred for the payload. But if I go with the gas/drw combo the truck should be pink and no one will want it. I get that.
So it's gas/srw with suspension mods to handle the weight or diesel/drw with minimum mods if any.
While I'm pondering that, why is it that no one is weighing in with an opinion on the Ford, GM, Ram issue. I understand that both these issue are hot topics (diesel vs gas and sfrw vs drw), which makes me feel somewhat better about not being able to decide.
Regarding brands, initially, I was leaning towards Ram, mostly of the nicer creature comforts IMO. But I received more negative feedback than positive regarding reliability. Most recommendations were for Ford and it seems that Ford has the biggest share of the market despite their pricing, which I understand is a bit higher that Ram and GM. So I'm actually leaning towards Ford at the moment.
Of course, if I go with a F-350 DRW diesel in the Lariat trim for decent creature comforts (since we will be travelling in it for a year) I'm sure to be shocked by the sticker price. But you only live once . . . which is why DW and I are taking this trip in the first place!
Thanks again for all the help everyone!