The Toronto Zoo is located outside 'Toronto' itself and all the way east of Toronto. Its a bit out of the way, but I think all outdoor safari/zoo/water parks usually are. So no big deal for the drive out here.
This is the only zoo I have been too, and I really enjoyed it. I brought my baby cousin here on a hot summer day. The park is huge prepare for lots of walking and bring comfortable shoes! They have open vans you can purchase tickets for and hop on when/if you are tired. Lots of great animals, a fair range of variety.The food/drinks are priced right around any other outing places.
Its a nice summer outing, get to enjoy the sun, spend some family time together with lots to talk about, enjoyable for all ages!