Where to fuel: as mentioned, in the Toronto area you can get it where they
fuel taxis.  Outside of the GTA, just get used to looking for the propane
cylinders in gas stations.  I like when they are mounted vertically so you
can see them from afar.  When you see a tank, look for what looks like an
old-school gas pump to dispense the propane.  Otherwise, I don't think they
can fuel a vehicle.

Or, just try this link:
https://propane.ca/fuel-station-locator/#/find/nearest?fuel=LPG&location=oakville,%20ontario&lpg_secondary=true

I tried a search for Oakville, Ontario and I can confirm that yes, the
Speers Husky station does, in fact, serve me propane.

Be cautious about going

Gabby