I know this has been up for a while, just some added info on a 2010 210... Not sure if you're was a similar setup but this was from my complete r&r of the propane regulators and hoses. Easier to overhaul the whole thing than to keep chasing seeping leaks.
You can see the new primary and secondary regulators but I recommend that every fitting be disassembled , threads cleaned and refitted using gas rated sealant. I use Rectorseal #5.
Removal - I first loosened the fitting at the main line from regulator to coach. Lefty loosey. I then removed the bolts attaching the black mount plate from the propane tank so that the propane "manifold" so to speak was loosened from the tank. Next was loosening the short black hose from the tank valve. Righty loosey and support the valve itself as you work the fitting. I also removed the BBQ hose from the secondary regulator. After removing the fitting from the main inlet line the manifold can be maneuvered out thru the tank fill access hole in the bumper. Reassembly is the opposite just remember the first connection needs to be at the main tank. I didn't need to remove or even loosen tank or hitch.
In my case I needed to be sure I used a vertical vent regulators with the vent pointing down. I also had to slot a couple of the holes in the black plate for the new primary regulator - just a hair difference in the mounting, no big deal. And important last step, leak/soap test every connection under a strong light, use a small mirror if needed to look all around every fitting.