Hi, we need to be in McCall the weekend of August 9-11. I want to stay at Ponderosa but of course the reservable sites are booked up. How likely am I to find a first-come first-served spot in the NW Passage section on a Friday evening? I don't want to drive up there with no chance of finding a spot, if that's the case I will camp at Lake Cascade. I emailed and called the Park with no response so far.