I was in training at Keesler during Katrina. Only a few hundered volunteers could stay to do clean-up, the rest were sent to Shepherd AFB. (I can tell you that almost all wanted to stay and help the community.)
For those who stayed, there was a lot of clean-up in the local area. The most helpful thing immediately afterwards was delivering MRE's and bottled water to the locals by the truckload.
I was stationed at Keesler from 1995 to 1996 for tech school.
As much as I hated it then, I miss it now.