You shouldn't need a generator or solar to dry camp for a long weekend. You *do* need multiple batteries (2-4) though.
You also need to track down your parasitic drains.
If disconnecting the CO detector makes your batteries last......well.........time for another CO detector solution. a 9V battery operated one, or smash it with a hammer, or something. IMO, a "spot check" of CO is adequate, but everyone has their own opinions. I say that because the only source you really have is your furnace. So run the furnace in the evening and check before you go to bed. If it's running properly, no concern. My parents camper doesn't even have a CO detector (oh the humanity).
Point being, be thorough about what's draining your battery, and address them one-by-one as required...also adding more capacity, probably.
Another common one is the radios. the "new fangled" radios these days always have some draw. It shouldn't be much (the one in your car won't drain the battery after 2+ weeks), but it's something. perhaps a well-positioned toggle switch solves that (made up) problem.