Nice, clean looking ride, rick!
I had a 4x4 90' F-350 crew cab w/460 and I could get 13 on the highway @70 mph. You don't want to know around town and in stop & go traffic. I was hauling the daily newspapers to the paper carriers' houses at the time and Sunday's paper would fill the bed completely and about 2' over the top of the cab (I had sideboards and a headache rack) and the back seat completely.
With limited usage the fuel mileage is less of an issue. I wouldn't be driving my Suburban if I was doing 15,000+ miles/year. At only 6Kish/yr. it's not worth buying another vehicle to drive around when I don't need it.
That thing will make a fine sled hauler!