Use Shane's big map to plot a route...perhaps get up to highway 9 but the roads mostly run the wrong way for your angle to get to Algonquin.
Maybe use Gmap and ask to "Avoid Highways" like so
https://goo.gl/maps/CBfU2bddvzy
do you have a smart phone for GPS
If you are going there and back in one day, then I'd suggest bombing along the highway to Barrie and riding backroads north of Barrie. Tomorrow there will be no traffic heading up there and you will be able to cover more distance in a shorter time, leaving you more time to ride the good roads up there.
On your way back, I think there may be a lane reduction at the very bottom of the 400, to get on the 401 west, so you may want to look into that and think about a different way to get to the 401/403.
edit - something like: https://goo.gl/maps/ZSL2LhXg3rT2
Ugh - one day and back roads.....get up early![]()
I'm leaving at 8 am, hope i can make it back to Hamilton by 10 or 11 pm
If you're planning on it in one day you'd best at least take the slabs on the way there. For the trip back down come south on 35 through Dorset, Carnarvon, Minden...down into Lindsay and then you can follow it back down to the 401 in Bowmanville. At least part of your trip will be somewhat scenic.
Google Maps does indeed have an "avoid highways" option on the desktop version and checking it out it plots a reasonably decent backroads trip up that way...but some highway is still going to be unavoidable, including the 401 trek back across Toronto if you take my earlier advice on a different route home.
Gonna be a long day no matter what you do.