Congratulations Satellite. Looks like a clean unit. It is a 1/2 ton, so your mpg will be better than a 3/4 ton. Be careful not to overload the weight rating. You can add helper springs to it along with tires with a higher weight rating, but the brakes are designed to stop 1/2 ton in a reasonable amount of distance. Water 8lb/gal,(10 gal=80lb), fuel 6lb/gal, (20 gal= 120lb). Generators, camping gear, clothes,batteries, Solar panels, groceries, all have weight. A 1,000 lb seems like a lot, until you start subtracting. I am 200lb, (some say dead weight). So that leaves 800 of cargo to be at the max. Make your furniture as light as possible, (don't use 2x4's if 2x2 will work). 1/8" door skin plywood often will work instead of 1/2".
You can get pretty creative with weight reduction. Ounces add up to lbs. One example is mirrors. They are often used to make the space appear larger. Mylar plastic weighs a lot less than glass. A foam matress, weighs less than most cotton futons. Canned food is heavy, don't carry more than you need.
With best wishes.