So I am pulling my tent trailer I built to Colorado in the runner. The question I have: is eleven miles per gallon normal? I can't believe it's so low but I've never really pulled anything other than a utility trailer.
I dont think its too far off from normal. I towed a drift boat from Seattle to SW Montana, over passes, with AC on travelling around 65-70 mph with a truck full of gear and a bag in my roof basket and got 12.7 on a tank...I think that trailer weighs more then my drift boat.
When I had my 4th gen V8 'Runner, I got 14-15 mpg pulling a lightly loaded utility trailer. When I tow nowadays, I use my '05 Dodge Cummins getting 18-20 mpg with awesome power.
I'm sure with you being at a higher elevation than me, you're going to get slightly worse gas mileage than me. But, when I pull my camper, which is close to 3800lbs loaded, and get into some hilly stretches, I average between 12 and 13mpgs. That's cruising steady at 65mph in 4th gear.