8K is the minimum you will ever normally see on any decently equipped Bronco or vehicle of its size. 9.5K seem to be nearly as or maybe even more popular now.
Do not waste your money on a 2K. Hell, most good 4x4 ATV's now come with 2500-4000# winches!
I had a 3500 mounted on my single trailer and it worked OK. If you just want it for rolling on the trailer, just mount a lighter one on there and then you can load all kinds of stuff with it. I have a new 8K for my 4 car ramp deck trailer that I will get around to mounting one of these days. It is a bit overkill, but that trailer does have a 50' long slopped deck, and if you are trying to drag a vehicle up with a locked wheel with a smaller winch, good luck! Besides, it was one of the econo MileMarker models I got cheap, so for only $250 or $300, why not.
If you mount if on the Bronco, get a 8-9.5K and then you can at least use if if you get stuck.
If you do not have a dedicated trailer, then just get a come along for $30. It will work fine to load onto the trailer. Plus you will not have a puny little 2K winch mounting on your Bronco that will look ridiculous like some mall crawler. ;D