Martin,
I'm not Mormon, but I've played one on TV......just kidding. I did, however, live in Utah for a total of about 4 1/2 years and knew/know many Mormon families. Not all of them are that prepared. Some cannot afford to be, some simply chose not to. Also, while many are prepared to some degree or another, they all indicated that they are also counting on community support from other church members, and at least some support directly from the church. This is not intended to, nor can it be, all inclusive of Mormons everywhere, but from what I understood this is pretty common.
I have a small book entitled "How To Be Prepared" written by Roland Page. Mr. Page is a Mormon (actually I think "Latter Day Saint" is the preferred term now) and wrote the book for Mormons. In it, he addresses many of the things you are wondering about. It is dated (circa 1973), but much, if not most, of the info is still pertinent. PM me and I'll let you borrow it. If nothing else, the lists of things you need are valuable and enlightening. When you're done with it, post it on the Lending Library forum, and anyone else who wants to take a look can have a go.
I would also reccomend a book entitled "Bad Times Primer" by C.G. Cobb. It has a decidedly survivalist slant to it, but is one of the better treatments of the subject that I have seen. Unfortunately, I do not have a copy to lend you.
Take care,
Andy