You also want to think about things you don't want sucking power. Do you have any 12V TV, or stereo that have remotes? Well in order to "hear" the remote they need power which means you have a parasitic load. Unplug them or put hard switches on them to kill them off dead. anything that is plugged into 12 volts may have a parasitic load even when turned off.
It's pretty cheap these days to convert your lights to LEDs which will help. They draw a fraction of the power of incandescent bulbs.
Catalytic heater.
Others have covered the generator thing pretty well.