Re: Parking Safety/Chocks
I'm pretty sure they adjust when you back up, like most other drum brakes. With big vehicles like this, and "Class A" driving, backing up is not something that is practiced except when in dire need. In addition I've found it takes a pretty hard brake to get any results, specifically the empty parking lot kind of stopping at speeds I would never do in reverse normally.
There should also be a pretty easy adjustment with a flatblade screwdriver if you're very far out. Keep in mind I can't get under my van at the moment to double check this, but there should be a flattened oval with a little rubber boot in it, behind which is a spur gear perpendicular to the opening. If you remove the boot you can roll the spur gear with a flatblade- it will only go one way (tighter) because there is a plate opposite that ratchets the teeth in only one direction. Adjusting this will tighten your parking brake. Removing the wheel and drum is also an option, especially to inspect if the adjustment kit is corroded, stuck, or damaged. The advantage of removing the drum for adjustment is you can adjust it redneck style, i.e. until the pads just touch the drum as you reinstall.
And a competent mechanic or brake place can do all this, but understand it's probably a fairly easy problem that might be solved by some hard reverse stops in a clear area.
Now all we need is some genius to realize we could apply superior drum brake technology to the front wheels as well...