When we got our Weber Q-220, I decided not to risk hooking into the MH propane system. I didn't want to have a 15' or so rubber hose carrying full cylinder pressure across the gravel and grass to wherever I put the grill.
I'd also heard of people who had hooked up to the RV's regulated side and found that the full motor-home regulator wasn't sensitive enough to control the low flow rate of the grill. One poster said that even on its minimum setting, the grill was still at 600F.
I decided to go with a smaller portable tank that the routine 20-pounder. I bought a "squatty"10-pound tank at a local hardware store that has the same size base ring as a 20-pound tank.. I then bought a base stabilizer at Camping World and bolted it to the floor of a stow-bin. It holds the tank base very securely and I have also put bungee cords through the tank handle to a hook on the wall of the stow-bin. In a major deceleration accident, I don't think the tank would break loose, as it's very close to the front wall of the bin, and the bin doesn't go through to the other side.
I get the cylinder filled to about half-full, so it's not too heavy to lift out. The set-up has worked fine for two seasons and there's no risk of blowing out (or accidentally cutting through) a high-pressure hose, or melting the aluminum Weber.
Frank Damp -Anacortes, WA,(DW- Eileen)
ex-pat Brits (1968) and now ex-RVers, as of 08 Dec 14.