So I'm at the Thompson Hotel and plan on visiting the Ripley's Aquarium today if a route neat there is better. I was looking at Google Maps and I noticed the lake is nearby. There are many streets to walk down south but which street is not blocked off to pedestrians and actually leads near the lake with an interesting place to hangout or a good view to walk around in.
Bathurst Street, which your hotel sits at the corner of, has wide sidewalks on both sides of the street, all the way to the lakeshore.
When you reach Queens Quay West you can then connect with the Waterfront Trail, and follow it and connecting trails around the lake. Turn right (west) for a comparatively less commercial view of the lake, ending at around Humber Bay Park, and left (east) to view ports, docks, marinas, etc., ending around Beaches Park, or to take the Hanlan's Point ferry over to Toronto Islands. Either direction will take you out 8-10 km.
And if you're tired out from your walk to Humber Bay Park, go back up to Lake Shore Blvd and take the 301 bus or 501 streetcar ($3, exact cash) east to Bathurst Street, and you'll be about four blocks from your hotel.