Sounds fine to me...if plans (or...employment ) change they only require 48 hours notice for cancellation so we could go ahead and reserve a site anytime. The price works out to about the same whether it is an individual site or group site. All of the tenting sites are all pretty close together anyway.
As far as partying, if it's anything like last year most of the party was at the Red Rock motel with Larry and crew...didn't spend a lot of time at the campground except to sleep. Might've been a campfire one night...
Portal also tends to be a bit of an organizing spot for trail runs.
How many nights you want to be out there? This is what I usually do: leave home on Saturday, overnight in Denver, hit the Rockie Mountains fresh in the morning and arrive Moab on Sunday afternoon to set up camp. The heart of the event is Wednesday - Saturday, although I think you VXers do your run on Tuesday(?). So then you have an extra day to sightsee, hike, go to Arches National Park (just down the road), shop in town, whatever. Depart the following Sunday and get home on Monday. So it is 7 nights of camping.