You would think that your F-350 would tow a Ranger without a brake system, and it will. As long as you give yourself plenty of stopping distance. But I will tell you, from past experience, in a panic stop, or on wet roadway, without a brake system in the "toad". You would think the F-350 has the weight/braking/mass to stop that 3000 lb Ranger in an emergency, but it just doesn't.
You have over 3000 lbs of mass pushing your F-350. If that situation ever happens, you will wish you had a brake system.
Then there is the liability factor...if your towing anything that is required to have brakes, by law, and you don't, you might not get hit by the cops if your involved in an accident, but if it can be proven that a supplemental system would have helped avoid the accident, civil law will eat you.
Take it from a retired cop, also was a traffic homicide accident reconstructionist, it is very easy to determine what occurred and if a brake system was involved or omitted, and would have helped to avoid the accident.
My post about this is not meant to scare anyone of force you into something. It's meant to bring to attention what is needed/required to tow safely.
Towing a small flat bed trailer with a lawn tractor without brakes is one thing, but towing 3000 lbs is something entirely different.
Grumpaw