I actually found this out there before with all the towing capacities listed and the Bronco's factory ratings are NOT GOOD. I can't remember exactly, but the models without the rear sway bar are only rated to 2,000 - 2,500 pounds. With rear sway bar they jump up to the 4,000 pound range and thats it.
Say all you want about proper load balancing, etc, the short wheel base just sucks for towing not to mention the crappy stock brakes. Last weekend I used my bronco to move a popup trailer that's not perfectly balanced about 15 miles down the highway and it was swaying pretty good because of the short wheelbase and slightly loose steering because of the lift (I don't think the popup even weights 1,000 pounds). Put the exact same trailer onto my 1500 Silverado and the sway almost completely went away just from the wheelbase. I can also confirm the swaying based on the wheelbase because my Mom tows the popup all over the place with her little RAV 4 and the sway is about the same as on the Bronco (ohh yeah, the RAV 4 is rated to more than the no rear sway bar Bronco).
Personally, I'd avoid trying to tow something as big as a 25' trailer any sort of distance with it, just not built for it. Also, the brakes are just plain bad, if you do tow it, make sure you have a good trailer braking system setup. On the plus side, with that 400 power won't be an issue.
1979 4" Rough Country Lift. 400. 35" Pro Comp Mud Terrains