I only found out recently about it, but last fall I actually made it up that way via Canal Street just by following signs but had now idea that connected at the time. From the end, it's a left out onto Hamlet >Court Street> High Street right onto Canal Street cross the Mass border and it should spit you out here: https://goo.gl/maps/QU1ipNoADtbRM1s68

although it does split off around 146 so you have to get creative crossing there, but once you do it connects over to the airline. I will warn that northern section is rough