Provided you get a flame safe stove, you should be ok indoors. Flame goes out, propane/LPG flow stops. The valve near the stove is good to have. We are not required to have an alarm sensor system with the type of stove. A new stove costs about the same as a good sensor system professionally fitted.
Insurers here require the system to be certified by a gas fitter, from bottle to flame.
It is important to get it right. In my experience investigating the cause of an explosion on a gas powered propane equipped boat usually starts with each regarded as potentially culpable.
Island Gypsy 36 Europa "Doriana"