I assume this is where you’re staying? That link should have just about anything you need to know about the area.
Here’s a mapquest of the Greater Toronto Area (Often referenced as the GTA). The red star is your hotel (assuming I have it right above).
‘GO’ transportation isn’t the city transportation (that’s the TTC). It’s the provincial transportation… usually used by commuters (GO stands for 'Government of Ontario, FYI) and the TTC is the local bus, Subway and LRT system. That might be confusing you a bit.
You can look up GO routes and maps here and you can look up the TTC routes & schedules here.
Never been to Vancouver, but Toronto is a pretty normal downtown compared to some cities I have been (New York, Washington DC, San Diego, Amsterdam). It’s a grid system, so most of the streets are East/West or North/South.
There’s the financial district (Bay Street), several shopping districts (Young & Dundas streets area), china town (Spadina), the ‘SoHo’ kinda-artsy area (Queen Street West).
Downtown is really close to the lake, so you can only get lost going one way (North), otherwise you’ll end up swimming in Lake Ontario (South of downtown). Wander too far East or West, and you’ll definatley notice. West is all highway, and East becomes residential (mostly). I’d stick between Church Street (on the East side) and Spadina (on the West side) and you won’t get lost. It’s only like a 4 block span.
The CNE grounds, Ontario Place, Skydome and the Air Canada Centre are all near the water.