There is not that much difference between those West Island Boulevards: they are wide, but not wide enough, they have traffic and there is almost no way around them. I think I would rank Saint-Jean and Saint-Charles as slightly better and Des Sources as the worst one, because the part between autoroutes 40 and 20 is narrower and because of the Des Sources-20 interchange is superbly inadequate.

My recommendation would be to either get a rearview mirror and deal with them (they are not so bad, except when stores close), or to use other streets until you reach highway 40. For instance, between Des Sources and Saint-Jean, you could ride on Fredmir, Roger-Pilon and Tecumseh until you reach Brunswick Boulevard. Then you'll need to catch Saint-Jean Blvd, except you will be just one block shy of highway 40.