Whirpool Bridge Route - Don't use the Niagara Parkway. From the QEW exit at Thorold Stone Road and stay on it as it curves and becomes Stanley Avenue. Turn left at next light (Bridge Street), which ends at the bridge by the VIA station (turn right and then go to the entrance. Reverse this to get to the QEW from the bridge - about 10 minutes.
Coming from QEW St. Catherines I find taking Hwy 405 then exiting at Stanley Ave (turn right) much faster. You would then go through one stop sign, one traffic light (which is almost always green ;-) until you get to a railway crossing. Turn left directly BEFORE the railway crossing onto Whirlpool Rd. which you follow to the end at River Rd. There, at the stop sign, you turn right and stay on River Rd past another traffic light until you get to the Whirlpool Bridge on your left.
Taking this route you have only two traffic lights which work very much in your favour and two stop lights, plus you don't run the risk of having to wait at the railway crossing.