Does small christian church group need reservations? Or is it first come first serve? Days open please? What are the fees to camp overnight? Is cost per person or per family?

Yes. Everyone need to reserve. If they are still available.

You do need a reservation.

We just had a great time with the Lord in our Mini Retreat, got there on a saturday afternoon and left on Sunday July 4th evening, we had to reserve in advance for the cabins and had access for the big sanctuary, the kitchen and every grill on premises. The cost was $35 per person. Try to invite friends too, the bigger the group you have more chances to use the big sanctuary.