Generally anything with propane connections/combustion chamber that is exposed to the outside air and sealed off from the inside, that propane will drop and hug the ground level and be dissipated by the wind or or if no wind will pool around the lowest level of the ground..
In other words most likely will not enter the inside of your RV to levels high enough to trigger a propane alarm unless you had a cylinder/regulator malfunction large enough to create a big heavy cloud of propane fast enough to engulf and surround your RV..
Propane alarm would be more like monitoring for propane pooling from INSIDE propane connections and in most cases your stove/oven connection and or valves.
