I would suggest going to the Maple Leaf lounge to do check in and get your boarding pass on the Air Canada ticket rather than going to RCC. Why would you want to go to RCC if Maple Leaf lounge is available? Is there an RCC in Toronto?
Maple Leaf lounges in YYZ are great. Free drinks (alcoholic and non-alcoholic). Free computers with Flyer Talk etc etc. Name me an RCC that gives you those.