Mr Rawles:  
Well, this is an area of knowledge where I do in fact have some expertise, being a caving professional.  I hadn’t ever really considered caves to be of much use from a prepping standpoint, but as an expedient shelter with a constant temperature they could have their uses.  

A bit about my background -   I have logged about 3,000 hours in caves during the past 5-6 years during which time I have been a ‘wild cave guide’ - meaning that I run tours through rugged and undeveloped caves - not the wheelchair accessible type.  I am also an active and trained member of the regional and national cave rescue organizations.   

The disclaimer:  Caves are inherently risky.  If you manage the risks properly, the danger level goes down, but if you ignore the risks they can be one of the most dangerous environments a person can enter into.  This danger chiefly arises from the darkness, the rugged terrain and from the remote nature of caves.  There is no recourse for help when in a cave – no cell, no 911 – except the people you have with you and the trip plan that you (hopefully) leave with a trusted loved or friend on the surface.   Read More Here