Welcome, Judith!
Travel trailers are measured from tongue to bumper, so I'd be surprised if the body was actually even 28 feet, maybe more likely to be 26.
I have some travel trailer experience and would like to point out some safety concerns (not necessarily problems, but concerns to investigate) with your rig.
Please be sure that your trailer's GVWR, which I looked up and is 7200 pounds, does not exceed your truck's towing capacity and that the combined rig loaded, gassed up, and with both of you in it does not exceed your F150's GCWR. For optimal safety you should have a significant margin. I looked up the F150 and depending on how it's equipped you could be overweight or ok.
The specifications I found were at:
http://www.fordf150.net/2009/2009-fo...ifications.php
http://keystone-passport.com/index.php?page=specs
The trailer ships from the factory weighing 5140 pounds. That could easily be 5500 by the time you take ownership, maybe more. After you load your stuff in it and have some water in the waste and fresh tanks, you could easily be right up to or over its 7200 pound GVWR.
Be sure that you're using a good quality Weight-Distributing Hitch, that it's adjusted well, and that you're using it properly.
As for saving gas with that rig, there may not be a lot you can do. You probably already need to air up all the tires to their maximum for the weight they'll be carrying all the time. You could get away with the specified minimums for occasional use but for full-time use you should have more.
Your best improvements might be from aerodynamic work. A cap on the truck with a deflector on the back might help. There is research about the shape of the rear of box trailers that should help.
http://www.nasa.gov/centers/dryden/p...ain_H-2283.pdf
I thought I remember that document having a picture of the best configuration being where the side/top/bottom walls continue for 8-12 inches past the rear wall but I don't see it now.
Linear Mode
