Having been, over the years, to other gatherings that were similar in nature to the wonderful Getaway, I'll throw out a few thoughts.
Lotsa space: This is Crucial. Without it you might have one big song circle with Ballad folk, Country players, Bluesers, Old Tymers etc. and the music tends to not satisfy as much as when you can 'get in a groove' with one style. At the gettaway there is room for several smaller gatherings, each one focused on a (vaguely) specific type of music. More fun that way I think. many of us jumped around from group to group and then tried to adapt to the 'dynamic'.
I've been places where folks complain the next morning that their group was 'hijacked' by some other form of music. That may sound trivial to some, but I understand what they mean. Take ballads....you get used to the 'story' mood, and if someone jumps in with an up-tempo Hank Williams tune it can be distracting. Having the space for each little group really allows people to get into their favourite 'groove'.
Even after all these years, I'm still pretty shy around strangers, so I know I simply HAVE to make an effort to go up to them and say "hi". It really manifests itself when you're lookin' for a spot to sit for mealtime. It's not the easiest thing to plunk yourself down 'mongst a group that seem to know each other really well....but when you do....you've just made some new friends, and boy, that's worth it.
I found the Getaway folks very welcoming, friends and strangers alike.