This is what I would suggest:
Check out Mrs. Wilkes website at
www.mrswilkes.com
People will start to line up around 10:15 to 10:30 for lunch. There is no sign for this place, just look for the line. If you go around 1 PM, you could expect to wait (standing outside in a line) for around an hour. They will seat as many as they can when they open at 11, so you'll be waiting until someone finishes eating, which could be about 45 min. or more. I haven't been in years (not a place you can get in and out of quickly on my lunch hour) but I think it seats 70 or so. That's jut a guess. They are only open Mon - Friday, so don't go on the weekend!
As far as the tours:
A carriage tour will cover much less ground (the horse can only go so fast), but you will learn a good bit about what you cover.
The trolly/tram tours cover much more ground, but they just point out the landmarks.
The carriage tour might slowly go by Jim Williams house (Midnight in the Garden of Good and Evil) and talk a little bit about it. The trolly tour might just have time to say "there is Jim Williams house" as you whiz on by.
I would make a stop at the Visitor's Center to get some brochures on the different tours, as there are TONS. Tours can be started at the visitors center (they mostly, if not all of these, will be the trolly tours). Most of the carriage tours are from city market.
Hope this helps.