There are nicer routes north than that and you have time.
Up ninth line to Steeles, right to Winston Churchill, left up through Terra Cotta ( King St is a lovely little twisty ), over to Mississauga Road and then North to the Forks.
Hang a right at the end of Forks omn HWY 10 one road south to the Grange ( there is a middle lane for left hand turns - keep your eye peeled for it - easy to miss and it is the first left south of the Forks ) and left, another nice bit of twisty up and down ( do watch the cross streets for bozos in a hurry that time of day and then north on any of the paved ones ( Heart Lake is fine )
Get on to Beaver Valley Road at Eugenia Falls ( you can cut right at Flesherton if you get on to 10 ) for good ride north then cut over to Bracebridge further up. Just look for the Eugenia Falls sign a few KM out of town to the East out of Flesherton..
Might be willing to ride up as far as Eugenie - do love the burgers there

Lots of nice areas ( Terra Nova as well ) to take a leisurely ride up then cut over to the bottleneck that is around Barrie.
PM me around 2 pm - I usually escape to the Shed that time of day anyways and happy to show you the quieter routes out of the city.
I'm at Winston and 403
Have a look at the first map in the sticky above.
This section
then cut east above Barrie.....far more civilized and relaxed route tho it will all be busy that time of day at least you'll have some fun roads....you could do that route in reverse on the way back Sunday. If you could bust loose at 2 pm - you'd have a much lower amount of traffic to deal with.
Bascially zig zag a bit up to Stayner then cut East across the top of Barrie . If you print that map out in several sections its good enough as a general guide
email me direct as an alternative
macdoc@macdoc.com
If not have fun.....you've got lots of time to explore.