I don't envy you, Susan. What that woman really needs is a kick in the pants, and you can't give her one, since you work for the church. How are you going to handle her?
Carefully. I don't think she's inherently a terrible and selfish person, just one who's gotten caught up in the mythology of wedding as Most Special Day of Your Life. She's the youngest bride I've worked with, and while I don't by any means think all young brides are more prone to bridezilla-dom, my guess is that this is someone who's among the first of her friends to marry, who's been sighing over the bridal magazines with her friends and taking their advice as gospel, and who also comes from a family that normally has big production weddings.
Also, she's not the one with ties to our church--the groom is the grandson of a member. We limit weddings to members, regular attenders, or the children and grandchildren of members, because otherwise we would turn into a wedding chapel. Our sanctuary dates back to the 1920's, which around here passes for old, seats around 300, and is generally a gracious building with elegant lines and good bones. So I have a tiny sneaking suspicion that they're marrying at our church rather than hers because it is such an unusually elegant building, and that the bride doesn't know the church well enough to have any conception of just how large, active, and busy it is, and how on any given weekend several things are going on, usually at once.
So, I'm not going to email her back right away, because I need time to research the one perfectly reasonable thing she asked me (current rental rate for a parking lot a local school rents out for weekend events, since the church doesn't have its own lot). And then I'm going to explain that while we make every effort to accommodate wedding couples' needs, that we cannot go so far as to push other church activities aside, because the church's priority is its ongoing worship, fellowship, and community service. Basically, the nice version of my c-h-u-r-c-h rant from last night. And I will spell out what her options actually are, what I can and cannot do for her, and let her choose accordingly.