There’s usually a sizeable contingent present. Not sure if there’s going to be a caravan down or not, but I believe there was some talk about it.
There are usually scheduled events/ mixers after hours, mostly put on by the various detachments, for example FISD, IOC, etc. Schedules are typically posted on each detachment’s forum.
Then there’s always the big Bash, details of which are posted on the main 501st boards. In fact there’s a thread on there that usually keeps a running calendar of the various after-hours events.
If this is your first Celebration, you’re in for a great time, particularly with all the out-of-con events!