I used a
Stehl Tow Dolly with electric brakes for 3 years until I had to sell that car anyway, and bought one capable of 4 down.
I did have to install my own breakaway switch, but it wasn't difficult. There are 2 separate wires running from the 7 pin connector, one to each wheel. In the hollow axle, where they run, I cut them and put connectors on, then I made a 5 wire connector bundle and plugged in both wires from the 7 pin connector, both wires from the wheels, and the wire from the breakaway switch. Worked like a charm.