what are the ages of the people attending because "young adult" could mean anything from 13 to 25, you know? if it's a teenage group, like 15 to 18, i think you should talk about how you can handle yourself safely at parties, etc. i wish my youth group had talked more about being safe, instead...
I think it's perfectly acceptable to invite your friend, just be very upfront about what the camp is about and what they believe. your friend can probably decide for herself if she'll feel comfortable there or not.
is it close enough to home that she could leave before the camp is over if...