Thanks for the query Mouse; it has given me the chance to give more detail as to what is expected rather than have things come as a surprise nearer the time 
Barlos needs a hardcore of maybe 7 or 8 people who can help set up the Feed Station ie setting up tables, laying out bottles, bottle collection area, pirate flags etc etc. The normal start time for this is around 7am.
Then extra bodies are needed to actually hand out the bottles, mix the High 5, replenish stocks of bottles, etc. The time for this is really dependent on where the Bike Feed Station is on the bike route. Last year, the main contingent arrived after the swim and that was perfect timing.
Basically it wll be all hands on deck from the start the first cyclist arrives. If the Feed Stattion is passed twice we have a fairly continuous stream for 4-5 of hours.
OSB are in contact and keep us updated with the position of the final cyclist, In previous years, people have been able to leave the Feed Station as the bike flow has decreased. I think the last cyclist went passed at around 3pm last year.
I would suggest to Barlos that, if they want, those who were there at 7am are given first refusal on being the first to leave. But at the end of the day, we are all adults and it would be nice to think we could all sort ourselves out and not leave anyone in the proverbial
It's also worth pointing out that the Feed Station is not suitable for really young children or pets. It is also not a spectator's area. If you use it as such, you will be roped in to help. 
All I can say is last year all volunteers were able to enter the Big Swim of their choice, however this was only revealed about a week before hand.
I know in 2011 camping was free, but can't remember for 2012. Maybe someone else (Raf or Seren?) could remind me?
