See in particular his post from a couple of years ago “How-to: Yonge St and Hwy 401 by bike” for getting around the mess. I’ve ridden the route with Darren and it works great.

Once past Yonge/401, You can use streets like Willowdale Ave., Maxome, and Henderson to connect to John St. or Green Lane in Markham. You can’t totally avoid Leslie, but it makes the ride much more enjoyable.

I have a potential client at 7 and Leslie so I may well be sharing some of that Markham cycling pain soon, either that or reacquainting myself with the 25D and 90 Leslie bus routes…