Camping Interior safety
CHECK YOUR FUEL LINES REGULARLY!
CO monitor near the fridge, fire alarm on roof (tells you when toast is ready too @@ ), Fire extinguisher on 'B' pillar next to sliding door (DO NOT DRILL AND SCREW LARGE HOLES INTO THE 'B' PILLAR - it's part of the safety frame and structure.
Although to be honest ~ I'd concentrate on getting out quickly and and letting it burn.
Also remember that glass esp. on a converted panel van, can be pushed out from the inside. Also have a glass hammer/seatbelt cutter under drivers seat (or within easy reach)
To break safety glass hit it in the corner NOT the centre (goes for double glazed windows at home too). I heard from a fireman that the stuff to use on engine (fuel) fires is AFFF (aqueus film forming foam) it also does not corrode as powder does so its easier to clean off. However do you fancy your chances of removing the conversion to get to the engine bay lid with flames licking round you? Ideally you would have an automatic discharge system in the engine bay from |www.firetrace.co.uk An LPG sensor may be a good idea to detect gas leak as well, good yachting/chandlers sell them.
Also mentioned: Fire blanket
There's nothing that will help you more than sitting with the family and working out exactly what would happen if there was a fire when you were in the van (same goes for in the house).
HM: A very good point Jen, talk it through with children, act it out, calmly working through the options and learning it 'by rote'. Also tell them if they smell anything like smoke or a fire, to let you know even if it turns out to be another car ahead or something else... the engine overheating usually makes a characteristic smell early enough to save the day ~ that many seem to ignore and drive on... Also, overheating clutch or brakes make that horrible acrid smell that lingers.