boost organised a members-only event at willowbank - it looked like a mamoth task as they needed a minimum number of cars to cover track hire and non-drivers still had to pay entry (and use the track catering service).
as you can see/read, it's a shite-load of work and effort (i never went but was interesting to watch/read progress on the organisation).
i'd suggest going (early) as a mob to a test-and-tune, appointing someone to liase with track officials to keep mob members racing together and to keep a running score. Having a common parking area and a few nominated photographers will help as well.