Go there for a couple of years. Have a kickass personality and be the hardest working skier at camp. Stay later than everyone else and hike. Get to know all of the coaches + diggers + owner. Ask for a job. Having comp wins under your belt helps as well as having PSIA and first aid certification.
Are you sure you want to be a digger? I'm not sure what the situation is at Windells, but at most camps a diggers life is fucking hard. Usually no money, always working their asses off, sometimes no free food, sometimes sleeping on the floor. Would you be willing to do that?