Well...according to many people around these forums you can tow whatever you want, its a ford it will tow anything mentality LOL JK.
The Bronco 2's weren't built really for towing, the short wheel base makes them impractical tow rigs and really cuts down on the tow capacity. IMO 3k would be really pushing the limits of a B2. A ranger it would be fine, but the B2 not so much. A pickup bed trailer, especially one from a Ranger, or similar wouldn't be an issue empty, but you start throwing stuff on that trailer and you'll quickly find that trailer weighs quite a bit more than you would expect. I have a full size truck bed trailer, and my B2 would pull it just fine empty but load it up and it was too much. My B2 had a hard time with the 2100lb car trailer I have just moving it around the yard. My pickup bed trailer does not have brakes, and I wouldn't pull it around loaded behind a B2. My B2 is gone now anyhow and wasn't even setup for towing as it wasn't wired for lights and given its lackluster results just moving things around the yard I wouldn't have wanted to tow with it period.
I'd definitely put an axle on it that has electric brakes regardless what you states regulations are. Anytime you can add a braking axle to something you are towing it just makes sense to do so. I wished at times my little ATV trailer had brakes especially offroad on trails where the trailer would want to try and pass the truck due to its lack of traction. Tires are another thing to consider, get good quality tires, and depending on what you are going to be travelling through, you may want to consider an all season or even an all terrain tire rather than standard trailer tires.
Don't get me wrong, the engine and rest of the drive train is quite capable of 3k towing but the short wheelbase really keeps you from using the vehicle to its potential. I didn't venture into doing anything to my B2 to get it tow ready due to the shape it was in. However, I'd think with some good springs, stabilizer bars, a good hitch system, it would do fine and add trailer brakes of course.