This winter is kicking my ass a little bit. Don't buy a 2wd pickup and expect it to do as well as a car in the snow. My crewcab diesel pickup has a locking rear axle and is helpless without a ton of skid loader in the back to give it weight. I have a mild slope to the front driveway and the standard proceedure is for my 9 year-old son to steer the pickup while I drag it up the driveway with my 4x4 Bronco II.
I bought this pickup because it fit my needs, was old, in great shape, low mileage, wonderful, and it was summertime and the warm sun was shining on my back and the furthest thing from my mind was 14" of powder and a hard-packed white glaze of driveway.
My little Honda car doesn't have a problem and it is light enough that I can pick the back end up. But the heavier goods are over the drive tires--and that is what counts on the slick roads. A pickup is very light in the rear, and the engine and cab are in the front. I need my pickup to haul stuff with. I can't leave 500# of tube sand in the bed all winter. I can't leave my skid loader in the bed all winter. So I have to go up the drive with an empty bed a couple times a week. Today after I went down the drive and pulled onto the road, I couldn't move. The rear tires were both turning but there wasn't enough forward push to get me moving. I had to rock it back and forth--no snow, just white packed ice--to get it moving enough to push off. I seriously miss the days when my family would fit in one of my 4x4 vehicles.
As to mileage, any Ranger is going to stink compared to a little car. It sticks up into the wind more. Hold a piece of plywood out of your car window and feel the effects of frontal area. It takes energy to push air out of the way. The tires are nominal in comparison. Fuel injected engines do a good enough job of mixing fuel and air that no gear change is going to yield substantial gains. You have to put an odd load on the fuel system controller to get it to suck--like 33" tires on 2.73 gears and drive it in 5th all the time. Going to all-terrains (I would go with mud terrains because anytime you NEED traction, the ATs are packed with whatever you are trying to get through) won't matter that much.
I think a 4-cylinder will get you 5 mpg maybe. It's only because it won't burn fuel fast enough to match the acceleration rate of the V6, not that it's more efficient. If you drive a 4.0 and pretend it's a 2.3, you do amazingly well. You have to let everyone beat you at every light, let the cruise kick you off on any substantial hill, and then you can pretty nearly keep up in mileage. It's not an efficiency problem at all. It's impossible to drive a 4.0 easily enough. If you follow an identical 2.3 equipped vehicle around all week, you will both need fuel at the same time. The 4.0 burns more fuel because it can, not because it has to. It can get much, much worse mileage because it can make almost twice the torque at any given rpm. But I want the damn torque. I'll suffer the few mpg because when I want to use my truck, it needs a little grunt. A 4.0 can do full-size jobs. It actually isn't heavier or larger than a 2.3 in physical size. It's a very compact engine for its displacement. You couldn't give me a 2.3--I wouldn't take it. You can get 20mpg with a 4x4 Ranger and 25mpg with a 4.0 2wd Ranger on a trip with the cruise on. I did a 720-mile round trip with a guy and that's what we got. He never seemed to need fuel when I did. He followed me and I went 65mph with the cruise.