Running before or during the Time of Troubles is problematic, as you'll be looking at really early FR stuff, and have to convert it over to 3rd Ed. There was a GenCon module set during the Time of Troubles, where the PCs were godly avatars, but I can't remember its name. You might be able to find it for download somewhere on one of the older ADnD sites, like
www.adnd.com
Otherwise, I'd personally go with the current setting, which is pretty available at any games shop. Easy to set up and easy to run!
Cheers,
TGHO