We found tha using the Lynx bus was really quite good. You pick it up at the TTC. They can give you a schedule there, or you can print one out from the Lynx site.
It is very inexpensive...about $1.50 pp, each way. Have the exact change though. It is about a 30 min ride. When you get on the bus, be sure to tell the driver you want to go to SW. He will drop you off at the entrance to the parking lot to SW. Just walk across it to the park entrance. When you are ready to go home, just walk back across the parking lot, cross the street, and look for the bus stop sign with the 'paw print' on it...it's almost directly across the street.
It's safe also...I know a lot of people think a city's public transit system is going to be yucky, but this isn't...a lot of CMs use it to get back and forth to WDW. We had several CMs as well as housekeeping staff on our bus.