There may be restrictions in tunnels or ferries. For example BC Ferries states
Remember, all dangerous goods must be declared at the terminal ticket booth or to a vessel officer. Failure to declare dangerous goods is an offence under Canadian law.
There follows a list.
Dangerous Goods Commonly Encountered by BC Ferries
. . .
Propane: Propane ...
A 20lb Propane tank can be safely transported in your mini van. It can also be transported unsafely.
Safely: up right, secured, ventilated, kept cool
Unsafely: on its side, not tied down, un-ventilated, allowed to get warm
The key is to keep it secured, upright, cool and ventilated. The problem becomes on a trip camping are you going to stop for potty ...
Storage methods for propane tanks:
Ensure the area is well-ventilated
Make sure that the tank is upright at all times
Keep the surrounding temperatures low by avoiding direct sunlight during summer
Avoid ignition source (lighters, matches, tinder, electric sparks, etc.)
When you're transporting the tank:
Leave the window or trunk slightly open to prevent ...