<human>: My truck does have a ball hitch on the bumper, it's an 2006 Ford ranger, V6 (3.0L), manual. 

I'm moving from Dallas to Michigan soon, and I'm looking for advice on how I should carry the mattress with me. Before, when I moved from Houston to Dallas (internship), I got a trailer big enough for the mattress to fit in. But my truck would struggle with going speeds over 50 mph and I feel that it's too much wind resistance for the truck to deal with. I had to keep it in 4th for small inclines, and only got 14 MPG.

I am renting a trailer from U-haul, but I want to get the smallest one. I'm putting a couch and some boxes in that trailer. What I'd like to do is tie down the mattress to the bed of the truck (lying flat on the edges of the bed) with more boxes etc underneath the mattress. Is that the best way to go about this, or should I carry it another way?

Can you give me the gist of the text in a nutshell?
<bot>: How would you carry a mattress long distance in the bed of a truck? Or would you sacrifice MPG and get a (big) trailer?