Welland Canal going downhill is quite easy. Uphill is quite a bit tougher because of the rush of water into the locks. If the weather is really hot you might want to do the transit at night. It is fully lit and you won't get baked in the locks.
Sorry for the bum steer about the Trent. I have not sailed on the Great Lakes for several years and forgot about the low water levels.
In South Africa doing lots of boat stuff. Departure north from Cape Town around December 15th. Arrival in the Caribbean around the beginning of February, after 5300 miles or so.