What are some of your favorite things to do
if you had 4 hours between flights?
Our layover is on the Southbound leg of our trip.
We have only been to SJU once since the makeover.
In past years we would wait it out at Franciascos' Runway bar.
Is he still working somewhere in the airport?

4 hours isn't really a lot of time - remember that's from scheduled touchdown of your inbound flight and scheduled take-off of your outbound flight. Your outbound flight will begin boarding 30 minutes prior to scheduled departure and it can be anywhere from 15 to 30 minutes from the time you land till you taxi, deplane and get out of the airport. Add to that travel time to get to/from wherever you want to go (figure at least 30 minutes) plus time allotted to go through the airport security check-point and you've probably only got about 60 to 90 minutes to actually do something. Personally, I'd stay at the airport and read a good book. If you are intent on leaving the airport consider going to one of the nearby hotels like the Intercontinental or the El San Juan (about 10 minutes away) for something to eat and perhaps spend a little in their respective casinos.

well, it depends when your layover is. We just took a trip to anguilla and had a 2 1/2 hour layover on the way there. my husand convinced me we had enough time to get lunch at the Ritz , which we did. Our connector was on the same airline (AA) and we didn't have to go through customs or anything like that. I'm not sure i'd recommend doing that for everyone, but it worked for us.

So, I think that I'll go to Duty Free, by a bottle, then buy some mixer and then get the cup out from my carry-on.
Ice? Hmmmmmmmmmmm

Ask one of the fast food places for a cup of ice
I would never venture out of the airport with only a 4 hour layover...people watching can be fun!