Onboard Generator or 2 Portable Generators + Solar + Battery

Even with your proposed lithium battery you’ll only have 80 AHs available for use. That’s not enough. And you don’t need 400 solar watts to recharge 80 AHs. The object with a solar system is to never use the generator except for AC and cloudy/rainy days. For less than $900 you should buy four Trojan T105s and have over 400 AHs with a useable 150-175.