You could do what we do and go a week or better. We run run the gen 2 hours morning and evening to get breakfast, shower and what ever, charging phones and anything needed. In the evening cook dinner, run an electric heater to keep us warm, and keep things charged, and cold. Then at bed time the charge level will hold the night with the furnace set to a level to just keep us warm enough to pottie, warm blankets. Now we do have two batteries but never start to run the charge level down. Three days at less than 12 hours gen time, 6 gallons max of fuel a $20 bill and there is no worry. Now I do see you are north so cold might be a problem and need a little more heat so you might want to run gen late in the evening and as early in the morning as possible, thats is what I do hunting in colder times.
LEN