If you want to save money both in purchase price AND mileage, get the 4x4 idea out of your head. I grew up in PA and ONT and rarely needed 4x4. A good set of snow tires is all you need.
My winter car in Ontario was an open-axle Caprice and if it was bad enough that I couldn't go out there was nothing open anyway.
"Need" and "4x4" are words you use for offroading IMO. I had a 4x4 chevy in PA and in 230k miles I think I used 4x4 on the road twice. I needed it for getting to the cabin which was 4 miles back in the woods over really nasty terrain.
Otherwise, the Qjet will return the best mileage you can expect. Don't be tempted to trade "up" for a TBI. Your mileage might drop considerably. The as-delivered curb weight on that truck is probably north of 4500 lbs so don't expect miracles. Be smart in your tire selection. 235mm is all you need, and don't use big knobby tread. Buy a set of H/T or passenger tires and one pair of snow tires in the back. Also skip the HD tires like E-range. A good P-metric or LT truck tire in C range is all you need and the drastically reduced weight will help overcome the gas you waste getting up to speed. It will also reduce rolling resistance.
A good mileage combo would be to use the TBI cam in something like a 305 or drop in a stock 4.3V6.