I don't have personal experience with the portable generators, but the summer of 2014 I worked with a guy that operated a 2000 watt Honda on a pontoon boat operating a couple of freezers 24 hours a day. He filled it with gas as needed during the day and when he docked at night usually around 5-6 pm. When he arrive in the morning at 7-8'ish is was sometimes still running and sometimes it had run out of gas. He checked the oil, filled it back up with gas and off for another day. He did this from May until September and the only problem he had was a spark plug that died.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof