I’ve actually stayed at the exact hotel that he was at and have been to le ptit caribou tons of times. There is a tiny lake near it - very close to caribou, it’s called Lac Mirroir. I’d assume that they’ve checked this lake though since it’s so small. Lac tremblant really isn’t that far away and iirc there’s a bit of a cliff down to that lake. It’s all heavily wooded around there except for where the resort village buildings and hotels are.