It sounds hokey as hell, but it wasn't, it was a great fic. Any assistance you could offer in tracking it down would be greatly appreciated. Thank you.
Edited to add: And dinara_n found it. It's You Know I Dreamed About You by Napricot. And it's just as excellent as I remembered. Thank you, thank you!
Honourable mention goes to janne_d, who suggested 20th Century Limited by Speranza. Not the fic I was looking for, as it happens, but also a good fic which I hadn't previously read.