I recommend highly the ride up from Kaladhungi (near the Jim Corbett museum) up to Nainital, for those who like a nice climb. Kaladhhungi has many MTB rides through the sal buffer forests around Corbett Park, and good road bike routes without much traffic as well.
And for a great place near Nainital to stay that is completely peaceful, try Mountain Quail Lodge (turn left right after Nainital tourist tax spot towards Pankot). From MQL you have a spectacular ride up to Kunjakarak mountain, no traffic, about 18 kms, up and down but nothing like the Kaladhungi to Nainital climb (you need MTB for this part).
From the complete trip Kaladhungi to MQL you'll climb 1800 metres over 35 kms, can be done on a road bike altho there is a rough patch or two. Its getting cold up there, need to do this before December or after February.
Don Greenberg