Consider a different brake system,, US-Gear Unified Braked Decelerator
Most control of any system (From the otor home cockpit) and a CHARGE LINE included no extra charge.. Plus it is nearly invisible to the towed driver (Small bracket on brake arm) nothing to stow when you are driving, no re-install every time you tow and indicator inside the motor home.. What's not to like?
That towed charge line consisted of basically three primary parts
1: 20 or 40 (Forget which) amp breaker connected to CHASSIS battery circuit on Motor Home.
2: Long wire (This was in 3 parts, I'd use 10ga or bigger, Part one was front (Battery connections center) to rear of MH (See notes below) part 2 was the brake umbicial (See note below) and 3rd part was a line from front of car to battery connection part with another breaker to protect it (The other of the two sizes,, NOTE in your case I'd use 20's both ends)
Notes: I now longer have that towed but have spliced in some Anderson power Pole connectors, made up an Anderson Umbicial, Addedn a 2nd line on the motor home to the FRONT (From the same breaker) so my new towed I can hook up either end.
Note: Battery connections point is NOT the battery, but the other end of a battery cable, On my motor home it is the battery control center, on my car the primary fuse box battery terminal.
Home is where I park it!