Well, I was going to reply to a bunch of these, but honeychile did a great job of it.
Regarding evidence of ancestry: I was one of those souls who had to both prove a new patriot and had a hitch in one of the links. (Couldn't find a marriage certificate.)
"Proof" is based more on preponderance of evidence, rather than only certain straight-line documents. In the above example, I used a combination of census records, published birth records, and a death certificate to prove one person's parentage. We never did find a marriage certificate, but it didn't matter.
honeychile - you'd be proud of me, I was just elected my chapter's registrar (HEEEELLLLLLLLP!!!!!!!

) so I'm going to be cross-checking applications and supplementals, etc.
The links everyone gave are a good start for basic DAR membership information. I'm helping some family members get started on their paperwork. If anyone has questions beyond that, feel free to drop me a line. (If you're in Texas, I can probably give you more direction since I'm working w/ that state. Sorry, honeychile, I don't remember where you're from, so I don't want to step on toes if you're a Texan too.)
Re: "snooty". AOPiSilver, I think you're right about that being equated with "older". I know very few ladies who fall into the "snooty" category, and it does seem to be associated with age. Case in point: the Texas Fall Forum was held in the same hotel at the same time as the Capital City Gay Rodeo. A few older ladies were wound kind of tight about that, but the majority of the younger ladies were like, "Woo hoo! Party down!"
Anywho, cool to see some other pages out there. And add me to the list of ladies who will help out w/ membership.
Adrienne