Are you dropping off at Avis Whistler? I've found the choice of cars to be automatically limited by Avis when choosing the one-way option.

Just came up to Whistler the other day with an "intermediate". It would have been a bit tight for 3, but if the third is a child, no problem folding down one of the back seats for the skis to fit in and there was more than enough room in the hatch for 2 suitcases.

But as always, when in doubt, get the bigger car/SUV.