You were actually at exit 7, Springfield. It's the Toonerville Trail, pretty sucky, only about 3.5 miles long, lots of fat people walking dogs. It goes from the Rec Center downtown to the Connecticut River. Completely not worth riding on, ever. Ever. Most of it paralells 4 lane Route 11, about 10 feet away. Might as well ride on the road.
Trust me, I live here! There's no MUP at exit 6, Bellows Falls.