Thanks again for all the posts. We ended up starting our drive later in the day then I'd hoped and didn't have time to stop anywhere on the way down. This is the 2nd time I've done the Atlanta-Key Largo dive. My daughter is a good traveling companion and it's not a bad drive. But.....It cost me about $300 just for gas. (4Runner - about 20 miles/gal). Add in tolls for the FL turnpike and it probably would have been just as cheap to fly, even with a rental car.
Anyway, dove with Rainbow Reef. Good as always, but the boats were packed. We had close to 40 people on board a couple of times including various instructors and students. We like to use them because they put a guide in the water with you, but one day we had 13 divers with one guide. Visibility was not good Thu or Fri, but on Saturday it opened up overnight and was as good as I've seen in Key Largo. Easily 80 + ft. Highlight of the trip was getting a good look at a nice spotted Eagle Ray on Friday.
One tip: There's a coupon at roomsaver.com for the Key West Inn for $69.95/night. It's just behind the Ramada at MM100, which is where Rainbow Reef docks their boats. It's listed as a one person rate and they charged me $20 extra for my daughter, but still a pretty good deal. I've stayed there 3 times now and prefer them to the hotels.