I've noticed this about Pathfinders, they seem to be pretty hard on the gas. But if you're out in the boonies, it's a good choice. The next step beyond that is a Wrangler - preferably an older one with the 4.0.
The other guys have already made the good recommendations so I don't have much useful to add there. I completely agree with your idea of getting an older econobox for your three-seasons driving, if it's just wet out the Pathfinder is like bringing a cannon to a knife fight.
If you want to maintain some inclement weather capability while still having better mileage, look for a Tercel wagon with the 4wd, a BRAT or a Civic Wagon AWD. They have comparable space to your Path (not the BRAT but you get a little pickup box) and all do surprisingly well when the going gets slick. The BRAT in particular will go much further afield than anyone suspects. Add snow tires and heave a set of chains in the back and you would be well prepared for all but the very worst and still get much, much better mileage than the Path.
I just looked on eBay and found a Tercel 4WD in Covington, about two or three hours up the road from you:
http://www.ebay.com/itm/Toyota-Terce...US_Cars_Trucks
I have a Subaru Forester which is brilliant in snow but its highway mileage at 25mpg isn't as good as I might hope. Newer ones do better, but I can't afford one.