Look for that non eth gasoline at stations near a marina, its popular for boaters.
Stabilize the fuel tank in the rv and run the genny to get that treated gasoline thru the genny's carb. I use a couple bottles of Sea Foam or StarTron. I have never had a bad gasoline issue using either one of them.
I exercise my generator for 30 mins every month or sooner bc I use my rv for day trips. Its probably best to have the rv on somewhat level ground when you run it.
Once a year around 150 hrs I change the oil with a syn oil. There is also a fuel filter that needs to be replaced every 450-500 hrs. along with the spark plug. A dirty filter will cause hard starting.
A good habit to get into , when you turn off a generator its best to shut off any heavy load on it. That will extend the life of the voltage regulator.