[gogoincar]

There are a number of small units, the hose+mask will end up taking the majority of the space, which is annoying but not sure of an easy way around that. (Maybe short hoses?) Resmed airMini is pricy but very small, needs an external battery, Philips makes a portable unit that’s a bit larger and has an optional integrated battery. You’d likely need a solar charger for backpacking. Humidification is probably the biggest trick - there are in-line moisture exchangers that help a lot, but if you have dry mouth issues it’s hard to beat a water chamber. Suppose you could boil water on a camp stove for use as well.

Def recommend try to get a study if you can find/afford it. I have a mild case, but getting used to CPAP was still life changing. That said, I find sleeping on my side is enough to avoid most symptoms for a few nights, and if I’m camping I stick to that (there are tricks for preventing back sleeping if it’s an issue).