I think I know the ride your refering too. About 6 years ago on a POS mountain bike I did a ride from Winston Churchill & Derry to Burlington. While I remember it being pretty verticle, I've rode steeper hills.
I did a loaded tour this year from Tdot to Tobermory. It's had it share of big hills and the one I remember most is when leaving Wiarton. Also, when circumventing Lake Ontario I recall a rather nast hill in Fairhaven NY...at the time it seemed 80 deg uphill.
I'm house sitting at the parents in Burlington all next week and hope to hit the halton hills ! Good riding (except during rush hour)