Double fail for 3.55's and open diff. lol
FYI, the weight won't be the biggest problem, the wind resistance will!
When I pulled an enclosed trailer with my sport trac from Oregon to Kentucky, strong headwinds slowed me down and semi's were passing me. When there wasn't wind, I was passing semis up the mountains, no problem. I also had 4.88 gears and 33" tires.
My trailer was only 6' wide. The ranger is just not well suited to towing a travel trailer, unless it is a pop-up.
Look in your manual, it lists a maximum frontal area as well as weight. For good reason I found.
2006 F150 FX4 Super Crew - Bilstien 5100s leveled 2", 35" KM2s, 4.56 gears, Detroit locker, Eaton E-Locker, Traction Bars, AEM intake, Xcal 2
2010 VW Golf TDI 6MT