Sounds beautiful, OM. I just googled it. Here is what it says about groups.

Over Night Group Rates for 10 or more
Overnight accommodations
$30.00 per person Based on 4 or more per cabin or tepee

Meals per day per person
$25.00 to $35.00

Use of School Building (24-hour period 1pm to 1pm)   
$100.00 per day

            + $8.00 each person not included in overnight accommodations

Use of ceremonial Tepee (24-hour period 1pm to 1pm)
$50.00 per day

            + $8.00 each person not included in overnight accommodations