You may be doing this already, but we have learned to watch WJ prices daily, and have even booked one way, then return when prices dropped. Someone has mentioned being a night owl and checking after midnight. Although not May prices, we booked WJ for $950 return for BOTH of us for October, and the prices have fluctuated between closer to $1000 and $ 1500 for the same flights. Good luck. It really is more convenient for us to leave from Toronto, but by May, there would be no worries about road conditions thanks to Mother Nature.