The rule of the thumb is, anything over 2000# requires braking system, some states are at 1500#. I would look at towing what your gonna do is with a dolly with surge brakes. Start adding up all the necessary things needed to tow without one. With a dolly you can tow a vehicle with the rear wheels on it, no need to worry about a transmission on the toad.
You might even look into renting one.
But, whatever your going to tow, I would have a certified weight slip. There is no guessing then if any trouble happens.