As a follow-up to my last post (three years ago!), our mother said she'd been married once prior to marrying our father, but we weren't able to find any proof of that.
Thanks to Ancestry continuing to add records, I've now been able to verify that she did, in fact, get married in July of 1952.
In Colorado, to which I was asked "What the hell was she doing in Colorado?"
That, unfortunately, is a question I'll probably never be able to answer, but at least we've learned this much.