The course is usually 6 months and then three years of apprenticeship with an additional 6 to 8 weeks of school each year. At the end you will have a gas ticket, be competent in installing hitches, 5th wheel hitches, replacing rubber roofs, electrical both 120 and 12 and you will know the code in your province (or state), refrigeration, appliances etc etc. It is a "performance objective" type apprenticeship and you need to be signed off on what skill at a time by a journeyman until you are done. I would start with the local college and see if they have the apprenticeship course. I suspect it changes from region to region. This is the way it is in BC.
Good luck and happy trails.