Insulation is an interesting topic, esp. if you have become a trailer restoration nerd like me. It is doubly important if the intended destination for your tin residence is subject to modest temperature swings from season to season. Quincy, California can range from 15-20 degree lows in winter to 90 degree highs in the summer. This makes the whole insulation challenge more complicated. So I have been reading up. This primer has been helpful. Give it a look.
Also, check this out: http://www.finehomebuilding.com/2009/05/01/which-rigid-insulation-should-i-choose
Also, although wikipedia won’t let me post the link, try Googling “wikipedia radiant barrier” and you will find a useful piece on the mechanics of heat transfer.
I have not yet ordered the stuff, but I am leaning towards 2″ thick rigid foam for the walls and 3″ thick for the ceiling with a Reflectix barrier on top to ward off radiant summer heat (making sure to maintain a minimum 3/4″ air baffle for maximum effectiveness). Any other ideas out there? I am all ears. email@example.com.