Whistler as in BC? Definitely DO NOT USE ROAD SHOES! Yes, I was shouting. There is NO WAY road shoes/cleats will work for you there. I've ridden Whistler and it is technical. You need a shoe that will let you run if you need to while on the trail.

Any friends/teammates with the same size foot willing to lend you a pair of shoes for the day?

Good luck! And I agree - sneakers are also not the answer.

SheFly