You need 3000-3500 for your rv if you want to run the ac. Otherwise a 2000 will work. For these you are looking at quiet inverter gensets that idle down to match the load. Good fuel economy and light weight. For big duties you are looking at open frame contractor gensets with big fuel tanks and constant 3600 rpm. These are the 6500 watt style and are cheaper for a reason. They are loud fuel hogs. The only reason I can think of to own one of these is for a specific intermittent need like a well pump, welding, water heater, hot tub, etc. Even house building contractors got smart and switched to the little inverter gensets.
Have a 4000 Harbor Freight generator. Good unit, not overly engineered or robustly built but it does the job. Not the most efficient unit nor is it quiet. I start it up every 2-3 months just to make sure it runs and the engine has not seized. It was given to me. The owner of the company where I work gave every employee one a few years ago after hurricane Sandy since most of us were out of power for 4-5 days. That way we could work from home even if there was a power outage or a blizzard.
Just joined the club I guess. Best friend saw this on CL and picked it up for $100. Took it to his small engine guy and $30 for tune-up. Haven't run it yet but should last a long time. Doesn't look like it has much use yet.
Just bought this one from Facebook marketplace. I have been wanting a dual fuel unit. Paid $500 for it. It has 10 hours on it.