I suggest you create a signature that lists your RV. That will help members in responding to your questions.
In looking at your profile I see you do own a DP so one of the air activated systems would be an option. The "box on the floor" systems will work, we had one for a number of years, (and yes, it's portable) but I didn't like having to deal with it, or find a place to store it when not in use.
We now use the Air Force one air activated brake system. Like similar systems, once it is installed it is a quick 30 seconds to connect the small line from the motorhome to the toad.
Jay & Peggy Monroe with Dolly
Can't take it with you - don't plan on leaving any behind
2016 Newmar London Aire 4553, Spartan chassis
Wrangler Unlimited toad