I think that your idea has merit. If I did not already have the trailer I would consider it, and maybe I will use it for plan "C" if necessary. In my neck of the woods if a quake occurs it is possible that it will occur on a 25 degree farenheit day with a 35 MPH wind. I can't think of anything less comfortable than a tarp shelter, a tent, or a hastily thrown-together shack. Your solution, while labor intensive, would provide a fairly snug, long term shelter.

Aftershocks are going to be a concern no matter what kind of semi-permanent shelter you have. This one reminds me of the old sod houses built by the pioneers, and those proved very durable-not to mention warm. <img src="/images/graemlins/laugh.gif" alt="" />

Regards, Vince