I too have a cabin that is absolutely off-grid and runs a generator to power all equipment. I connected the generator from the shed to a breaker box. I manage a 240v with a 5000-watt generator system. I also like to include a solar or battery bank in future. But for now, when the generator is working it is just the same as being at home. I'm not confident about your needs or questions. Because I have to do a lot of research and experimentation on your topic. Since I'm a beginner and I only knew little about these but knew some electrician
they can do a ton of help. But from my fewer knowledge, I think you need a disconnection when the SO cord enters the cabin.