Re: Do I need CO detector and LP detector
If I were you, I'd get both. They do very different things. A CO detector detects carbon monoxide that usually comes from a fuel burning furnace, stove, generator or other appliance that's not working properly. If you run your engine and the interior of the van has leaks, carbon monoxide can get inside that way, too. Carbon monoxide is a gas that's odorless, tasteless and colorless. Carbon monoxide will first make you very sleepy, then will put you to sleep—sometimes permanently. An LP detector will detect propane leaks that can explode or catch fire as soon as they meet a spark or flame. Even if there's no fire or explosion, an LP detector may save you some propane and money, if you pay attention to its alarm and fix the leak. Propane stinks, too.
Be sure that you follow the installation and mounting instructions on them. Carbon monoxide and LP gas behave differently so the location that detectors should be mounted are different. Carbon monoxide can mix with the air but LP sinks to floor level. After you install them, test them so that you get familiar with the particular sounds that each one makes.
I'd also get a good smoke detector. For smoke detector ratings, check out Consumer Reports. If you don't have a subscription, go to your local library and photocopy their article on smoke detectors.
Compared to the cost of a totaled RV, these things are cheap insurance. If they save your RV, they're great. If they save your life, they're priceless.