I thought the same thing too re: Caitlyn being to "young" of a name for her. While I can't imagine her as a Joyce, Denise, or Shirley, Lynn immediately came to mind (probably because of CaitLYN). I could see her as a Lynn.
Brenda would have worked well, though I think Lynn would have aged better. I happen to like Brenda, even though it's quite dated right now. It's spunky.