OP - I'll try and take some time to get you across from Markham on an interesting route
( maybe some one more familiar can get him across from Markham to the Grange and Forks tho
new rider needs care on the Forks hairpin.)
including White Church Road, The Grange east of 10, Forks of the Credit, Appleby Line, 4th Sideroad over to 1 sideroad and across the backside of Waterdown etc down through Snake and across to Dundas and Ancaster.
After that you want to hit Dover via 6 ( boring ) then along 3 ( there is a very nice cut off down to the the Lake at Selkirk and just stay right along the lake there - slow and windy. to to Port Colborne
and down to Fort Erie via Crystal Beach and some of the back roads there ( follow the lake ) to the Niagara Parkway. Take the Parkway through the Falls
Then come back along the Niagara Parkway to Niagara on the Lake - then through St. Catherines along 8 and jump up to the top of the Escarpment to catch Ridge Road to 20 - then down to Lakeshore ( good fish and chips shop )
You could head back along the Lakeshore all the way to Markham if you want tho the street car tracks might be annoying.
In the meantime check out this for some of the backroads out of Markham. These are newbie friendly routes done up by my riding buddy
http://wingnutty.ca
I helped him with the escarpment route north of Burlington.
•••
BG
OK. I'll try to come up with more helpful directions - since I live in the area, I tend to just point and go and don't know the names of half the routes I take - Ridge Road is a 10 minute drive from me and Niagara Falls is 45 minutes or so
ain't that the truth - been riding along the escarpment there for 40 years and still haven't a clue on some of the road names. It's one of those - that looks interesting routes...
BTW OP there is a really sweet but short section in Ridgeway to the north called Split Rock road ( really Ridge Road ) which is one of THE nicest stretches of twisty with elevation changes ) but you will have to search it out. I grew up there but hard to direct you.