Theres a couple of threads on here about Ontario/Muskoka riders....just search for them. I ride in Bala, which is on Lake Muskoka and if you find the right spot aka my spot there is always butter.
i stay and ride at my cottage on muskoka for two weeks and i go up every weekend during end of may-beginnig october...at least i hope esspecially this year. I ride at the muskokas but i've never heard of grand river???? is it near T.O.? or Muskoka}?