Hi Jess,
basically they are not set in stone as coaches wait until they know the numbers to decide where and when they want to hold the camps. Typically they try use cheap outdoor venues as long as the weather holds.
Would guess that there are going to be about 4-5 camps before Oceania, with the later ones only for the selected teams. Camps tend to be travel equalised and any surplus goes towards cutting the over-all cost.
hope that helps.
thanks