Could a civilian aircraft in distress land in Area 51? Just curiosity, but in case of a real life-threatening emergency (where you can't fly to closest airport or strip), would they (Air Force, military or whoever) allow the plane to land on the Area 51 airstrip? Have there been any occurrences that we know of?
R-4808, the restricted area around Groom Lake, NV, is restricted at all altitudes.  It is also surrounded on multiple sides by other restricted spaces and MOAs.

No routes, low-altitude or high-altitude, go through the area.  No one has any business being near there to begin with, so no one will have any emergencies in the area.