Riltri,
Without looking at the garage with my ASHRE guide under my arm, I really cannot answer your question. I don't believe that anybody else can either.
If the space is insulated and relatively tight, it just might work. It also might not.
If you are worried about the contents of the garage freezing, then put them in the coach with your little heater also inside the coach. Leave the reefer running to contribute to the heat and there is a real good chance that everything will work.
If you think that there is a real good chance of freezing the drinks, put them all in a secondary containment so that if they do break there is little to clean up.
Matt
OH, and an experience.... If your IPL looks frozen, don't pour it out and drink it. What you have there is just the alcohol that froze out. You really don't want that. It sounds good but the next morning you will know it was a mistake when you look at the half-full bottles you emptied.