I've done this ride on the Trans Canada Highway. The shoulder gets pretty small to virtually non-existant after a while on the 1a. However, the 1a isn't as busy of a road and is more scenic IMO.
As for getting out of town from Sunnyside, you can take the Bow River bike path all the way to Bowness. Then hop onto the Trans Canada at Stoney Trail. If you decide on 1a, take Stoney Trail north to Crowchild Trail / 1a.
Have a great ride.
T.J.
