I would be helpful to know the model and year of your rig. What solar package do you have? What kind of batteries? When I boondock I use a portable battery pack for my cpap. I don't have lithium batteries. I also don't have a residential frig. If I ran my cpap on the trailer flooded batteries they would be dead in the morning. If you have lithium you have a shot but I don't think running your frig over night with flooded batteries will cut it.
Tony & Donna
2022 Montana High Country 295RL, Solar Flex 400, Onan 3600 LPG, 2K inverter, 200AH Lithium. 2020 GMC Denali 2500 6.6 Duramax, Demco 21K Auto Slide