This is the power system that I ended up with on the off grid camper trailer. I added panels and batteries until reaching the balance point between power generation and battery usage. I have never lived in the trailer, but did enough testing that I know the system will work as-is in the summer, and then I have a supplementary solar array for use in winter, but I would expect to heat with propane in the winter. In retrospect, I don’t think it is cost effective to rebuild camper trailers like this for off grid use compared to just constructing small cabins.
So I ended up with around 450 watts of 12v power production, and 400amp hours of deep cycle battery storage, this trailer using true deep cycle batteries and not the RV/Marine starting batteries that I recommend with mobile workshop. What you see here runs all electronics including TV, stereo and laptop at the same time, can run a small fridge, all lights, intermittent use of small electric heaters, fans, rechargers for power tools, and some light duty power tools. It runs the microwave but not very well, but will not run the air conditioner.