FI to Iceland is the way to go non-stop as I was there on the Edmonton Trade Mission March 8-12!
If you don't rent a car, buy a shuttle bus ticket on the flight as KEF is about 50 km from Reykjavik and a cab runs about $120 one-way!
The best time to go would be in February 2015 for the Reykjavik Winter Lights Festival when Edmonton is going to be the Guest City!!