Well, the Atlantic Coastal Route pretty much goes along northern CT (I've done this section) and Stamford is right off I-95 in the southern CT. I assume you want to go west on the Northern Tier as the Atlantic Coastal route actually connects to the Northern Tier, but in Maine which I would assume would be out of your way if you're going west.
ACA has an Adirondack (ADK) loop that goes from Schenectidy, NY and passes the Northern Tier, I'm guessing near Plattsburgh, NY and also somewhere out west (I'm simply looking at the route maps which doesn't state cities so I'm just approximating).
So, basically, it looks like you should find a route from Stamford to Schenectedy.
Once you go north of Stamford and away from NYC, you really shouldn't have a problem with picking any county road and you should check out CT's DOT as I believe they have a bicycle suitability map for the whole state. NY does too, in a way, but they publish specific routes and some routes are actually signed with a bicycle sign and a number below signifying the route. But I've done some riding in and around east hudson and CT/MA border and you really can't go wrong other than staying off the interstates (I-95, I-87, I-84, I-91), etc. etc. Northwest CT, Columbia, Dutchess counties in NY are very nice places to ride and you'll find a lot of good places.
The one caveot is you'll have to find a way around Albany but I think that should not be hard. Outside Stamford itself, Albany would be your next major urban environment between Stamford and Schenectady...
Check this ConnDOT website and get the map:
http://www.ct.gov/dot/cwp/view.asp?a=1380&q=259662Let me know if this is helpful and if there is anything I can help you with...
Jay