I have cycled that trip a few times in both directions using different routes and none are what I cosider either enjoyable or safe. Loaded touring thru Toronto is very dangerous. If you are use to urban riding in traffic then you will be right at home. If you follow the Waterfront Trail there are some sections that are quiet and peaceful. You didn't say if the tour to Niagara was the whole trip, you could also transport your bicycle to Niagara and ride around the area. This area has some of the best bicycling routes that I have rode in Ontario. You may want to pick up a copy of the Golden Horseshoe Recreational Map at most any LBS or at http://www.fedpubs.com/mpchrt/maps/rec_trails.htm, this is a great map that I have used many times. Are you riding loaded for camping or light credit card touring, on or off road, how far and how many days? There is something in the Niagara region for any type of touring. You could also consider going over to the USA, there is also some great quiet touring routes over there also like New York State bike route 5 or the Seaway Trail. As for bike shops there are many in the area and are easily found in a phone book if needed. You should carry some basic tools and remember your helmet. Enjoy