It's a diverse and mixed bunch. Usually about 12-15 people per house, usually one house, sometimes two. There are also a dozen or so day trippers that head home after dinner. Not everyone there is a big drinker. Some don't drink at all. We're generally an older, pretty laid back crowd. I'm probably bringing my 11 year old. This will be his fourth gathering.
The houses are co-ed. Last year I (female) shared a bunk bed with Cirque's daughter. A couple men decided the living room was more comfortable than a top bunk. One family included a very cute toddler. Everyone was flexible and helpful. A fun time!
The details for a shared house are usually sorted out via PM. Usually one person is the coordinator for a house for making the reservation and handling the money. Last minute additions are common.