The only "detector" of interest to me with our rig in our garage would be the propane detector. I do turn off everything and also turn the main propane valve off at the tank. Given we are in the garage multiple times a day, we would be able to smell propane if there was a leak. I am not even sure I would hear from inside the main house, the propane detector going off inside the closed-up motor home.
In general the industry does not recommend storing propane indoors, so I am "officially" not following protocol. But the same applies to everyone storing indoors their motor home, travel trailer, pop-up camper, anything with a propane tank. It's a safety matter that I think goes a bit far considering our tank is well protected from any kind of impact or drop damage, and we are often in the garage able to notice such an odor.
There are so many RVs of all sorts that are stored indoors. I am fine with our particular arrangement with the batteries disconnected.
