After the second coffee...

From a "user perspective", mounting a fire extinguisher has IMNHO two major
attributes.

1.  You MUST be able to reach it from outside.

2.  You MUST be able to employ it without having to think about it.

My personal recommendations are:

One sitting behind the drivers seat so you can grab it on the way out.

One sitting beside or behind the passenger seat so you can grab it on the
way out.

Believe me, volks, if the fire is inside your first move is outside.   Then
you notice you have the extinguisher in your hand and set about trying to
put out the mess.

The other guy's fire is always outside.

The two most likely areas for a "fire" are the engine compartment and the
"kitchen".  When in the kitchen you exit the verandah, with the extinguisher
in your hand of course.  When in the driver seat you exit...yep, with the
fire extinguisher in your hand.

Most important have a professional check and re-certify powder or CO2 once a
year.  Halon is certified by weighing it (it's a gas) for the small
cannisters and by pressure guage for the installed or larger cannisters.

Take a few minutes to visit your local firefighters and have them instruct
you how to use your extinguishers.  Worth the effort.

At the campsite fill the ever present white plastic bucket with water.  Nice
thing about the white, you can find it quickly in dim light.

Fire suppression systems are rather like parachutes, always a nuisance until
you need 'em.

cheers,

pensioner