A 48v power inverter would be a practical choice for this treehouse if the battery bank is large and the goal is to run AC loads quietly between generator sessions. Compared with 12V, a 48V system can lower current for the same wattage, which helps with cable sizing, efficiency, and larger inverter capacity. The generator can still handle charging when needed. I’d match the inverter to real load demand, surge requirements, battery capacity, charger limits, grounding, and breaker-protected wiring.