Windham County from the 1824 map of Connecticut:
You can see the main road from Brooklyn to Windham is what is today known as Windham Road or Brooklyn Turnpike. The more northerly present day Route 6 which would run to Hampton thence through North Windham to Willimantic isn't shown.
But this was before the Turnpike company improved that route (1826) and the map clearly shows it was before the Turnpike built present-day Route 6 from Brooklyn Center to Danielson in 1845
THE WINDHAM AND BROOKLYN TURNPIKE This road extended from the courthouse in Brooklyn to an intersection with the Windham Turnpike in Windham about a mile east of Windham Green and near the scene of the famous Windham Frog Fight It was built by the Windham and Brooklyn Turnpike Company under a charter granted at the May session of 1826 and was probably completed during the following summer It is now the direct road from Brooklyn through Howard Valley and the northerly part of Scotland to Windham Green or Old Windham. The corporation endeavored to make money for nineteen years moving its gates and altering its location in the effort evidently with some success for in 1845 was willing to take over the road from Brooklyn to the bridge over the Quinebaug at Danielson and bear one half the expense of the bridge Probably the bridge had been recently washed away and the town was willing to make such a trade to secure a new one On this new road the company was allowed to erect a gate with half tolls
(From the Turnpikes of New England and Evolution of the Same)
Another interest road is Route 97 north of Hampton -- the original "main road" split from present day Route 97 and instead headed over Station Road and Morey Road towards Eastford, and back in 1824 to Ashford via today's Kennerson Reservoir and Bebbington Hill Roads.
I haven't narrowed it down, but I believe much of the section of today's Route 97 from Station Road to North Bigelow Road in Hampton is a modern creation in the early 1900s to create the present day connection to Abington; previously traffic to Hampton would've gone down North Bigelow and Hammond Hill Roads.
And now even older -- from a 1766 map of Connecticut:
I haven't figured out the exact location of the old north town line of Canterbury -- it was somewhere between Beecher Road (which aligns with today's north line of Plainfield, from which Canterbury was taken) and Fairgrounds Road.