Air brake knob
On our 40 ft Holiday Rambler the brake knob is on the console between the driver & the left wall of the beast. A old style wooden spring clothes pin would be a good fit over the exposed portion of the shaft. I would slide a piece of vinyl tubing over the center part of the clothes pin so it won't scratch up the finish.
I also usually dump the air out of the system so the "Spring Brakes" or so called "Emergency Brakes" are applied anyway, just as a back up.
You've gotten a wide range of ideas here, you just have to decide what works best for you!
Stan & Evelyn Haithcock, Baltimore, MD. 2008 H/R Ambassador 40' SKQ DP 4 slides, 04 Avalanche,
SMI Air Force One Toad Brake, Blue Ox Advanta