[Big Dave]

If you are serious about your towing and what FE, I'd recommend getting a late 90s (1997 or later) Ford Super Duty or Dodge truck. The Ford has a Powerstroke (International 444) engine. If you look, they can be had with a ZF-5 manual. The Dodge comes with a 12-valve Cummins 5.9 diesel and a NV4500 transmission.

For your load these trucks are bulletproof. They are big enough that no trailer ever bullies them around even in the worst weather. The drivetrains are so stout you can expect the trucks will eventually rust out around them working perfectly.

You get a stick version and with even rookie hypermiling MPGs in the 20s are easy. Read up on what aerohead says about aerodynamics and maybe you can get into the mid-20s.

Best of all, for your light (by the standards of these trucks) trailer will not degrade MPG like it will for smaller trucks.

The Ford is more stoutly built and has much better brakes than the Dodge but that solid construction comes at a price. The Ford is a good deal heavier and that exacts a MPG penalty running empty.

4x4 diesels go very well in the snow.

Ten or twelve year old diesel trucks can be had at reasonable prices.