I have an upcoming trip BOG-YYZ-GVA, with an 11-hr layover at YYZ between 7:00 and 18:00. I suppose I can use the AC lounge upon arrival (I'm *G traveling on paid J) to shower and have some breakfast, and am thinking of heading to town for lunch and a visit (and possibly meet up with a friend). Is this easy to do? In particular:

1. Is there a locker or baggage service to store my carry-on bag (backpack with laptop) at YYZ?
2. Is their an airport bus service - frequency & travel time?
3. What would you suggest I do and see in Toronto for the day?
4. Will I need to pay any extra airport taxes? (Years ago, YVR had some sort of airport improvement fee that was payble upon departure.)

Thanks!