Rick, genny run time is based on the given load. If it has an eco feature and only running lights, heater fan, it'll run a long time depending on the tank size. Powering the AC/microwave,etc, it won't be very long in comparison.
2012 Eagle 320 RLDS
2012 Ford F-250 Crew Cab FX4, 6.7l PSD
3.55 E-locker, Timbrens