Most online bike routes around Musselman's Lake (such as this one from Warden to Cedar Beach on the shores of beautiful Musselman's Lake) follow Ninth Line, on the east side of the Lake. I found this part of Ninth Line to be a bit narrow and uncomfortable for cycling, since there tight turns and are no shoulders. A better alternative, in my opinion, is to go along the west side on quiet residential streets. There's a section connecting Connor Blvd to Cedarvale Dr that is closed to motor vehicles, but accessible by bicycle or on foot.
Musselman's Lake is a tranquil community with some awesome views, although most of the shoreline is privately owned. It makes for an excellent rest stop. Connect to Ballantrae via Aurora Road to the north, and to Stouffville via Ninth Line to the South.
Here is the trail connection between Connor and Cedarvale on the north side of the Lake
Ice cream shop at Ninth Line & Cedarvale
Restaurant at at Ninth Line & Cedarvale