Sounds like we use our campers about the same. We have a 2018 montane 3120 RL. I think the big power draw is the refer. Even running on propane there are two fans that are always running. I need to set up some metering systems to learn where the power is going. I’m not spending 10-15K or more for a full solar and lithium setup. If we liver full time it may be different and when we retire in 1-4 years our needs may change again. For now I just want a simple reasonable cost system that will support us for 4-6 days.