I'm not suggesting anyone follow my example, but I have to plead a special case.
BigFoot is ALL-Propane. We are in South America and have experience wide extremes of temperature from over 100F to well below freezing so we either run the aircon via the propane generator, or the furnace.
Propane is fairly widely available, but usually only as swap bottles and there are very few places that will fill our American bottles.
So we have become experts at gravity transfer between local swap bottles and our bottles. Extra complicated by the local bottles being too big to fit into our gas locker. Even more complication because you can't swap one country's bottles in an adjacent country.
Real pain.
So I now have a total of three local bottles and the only place to carry them is under the dining table or in the crew cab. Usually they are empty as we transfer the contents into our bottles asap but there have been times when one or two are full.
Yes, not ideal but it is either that or have no source of fuel.
In the US?? Not so necessary but if I needed a bit more endurance I would lash an extra bottle under the table and take it out when I arrived and use an extend-a-stay to empty that one first (assuming it was a bigger bottle than normal)
One slight safety precaution is to carry it upright if at all possible and even better, buy a brass POL blanking plug and screw it in the internal POL thread.
Better still is to have a propane alarm installed.
Not a good example, but just about every kitchen in China has a 20# bottle with regulator sitting in the kitchen next to the stove and over two years we survived the experience