I know how to get there, but there's no good way. I'd say go east on Hooker (the little street on the south end of the Y) down to 1st. Left on 1st down to Arthur (7-11 on your right). If you've got the nerve, go right on Arthur and take the left lane, Corbett will be on your left a block or so after you go under Naito just past the 7-11. It's really dodgy, though.
Instead of taking the lane there, I'd cross Arthur and take the northside sidewalk - be really careful where you come out under the overpass and need to cross - cars are flying from the Ross Island bridge on their way to Naito there and will mow you down. Go straight across and hop the sidewalk on the other side and carry on straight. Corbett will be where your road ends in a T. Take a left, go downhill and turn right at the bottom of the hill and you'll be on your way to South Waterfront. Does that make sense?
Otherwise you can go part of the way back downtown and turn right at Harrison and go all the way to South Waterfront alongside the streetcar. Once you cross Naito on Harrison, you have a bike lane the rest of the way.