Departures: now–limited December dates, January–mid May, 2017
Returns: now–limited December dates, January–mid May, 2017
Looks like after mid-May, the price increases to $1200
Check date availability on Google Flights and use those dates to book on Priceline , free cancellations within 24 hours of booking
My sample travel dates in images
From BOS: April 22-May 6 (2 weeks) - via Air Canada
From ORD: April 22-May 6 (2 weeks) - via Air Canada & United Airlines (17 layover in Toronto...2 trips in 1??)
Please note that while this fare is valid at time of posting, fares can fluctuate in a matter of minutes/hours/days.