Has anyone out there done the Le Petit Train du Nord by bicycle? Wondering about trains, subway rides from Montreal to Saint Jerome . Is it possible to leave Montreal, early in the morning by train or subway and get to the Saint Jerome train station, in time to catch the Autobus shuttle to Mont Laurier which says to meet between 8-9?

Probably not.
The earliest weekday train arrives at St Jerome at 08:22.

This shuttle says they leave from Montreal but there's no other info. Contact them. Transport de vélos piste cyclable des Laurentides - Autobus Le Petit Train du Nord