I used to have a '64, maybe it's been longer ago than I thought.
Since you don't have a mustang right now, you ought to just cruise around the forum and see what section you enjoy the most. I'm a fox nut, so I think the most entertaining is the '79-'95 section.
There are a bunch of techs here though for just about any area of a vehicle. If you ever need help, just post a new thread. If you're not sure where to post, put it in the fox general talk section and I'll be sure the right guys see it
Plus it's pretty easy to be part of the community here, bunch of good guys around.