It is important to realize that ALL regulations on any water body in Canada are federal regulations. The Province and your municipality cannot create regulations on boating in Muskoka or any other lakes.
In Ontario, Transport Canada has delegated enforcement to the OPP.
The following are useful links to the regulations and information about them.
Canadian Coast Guard: Aids to Navigation System
Schedules with the restrictions for VORRs. This is where people can search for their waterbody to see if there are any restrictions already in place.