Nothing like firing up the nuclear aircraft carrier to pull out tent stakes, eh?
Indeed, JUST to charge up the battery (and sounds like in your case you should have a couple, not just one), even a 2,000 watt generator is more than plenty. To run the microwave (when, it should be noted, your converter is trying to ALSO charge up the battery) does require a 3,000 watt class generator, which is vast overkill JUST to charge up the battery.
A 2K PSW inverter such as
this one, if either wired to just power the microwave, or with the converter circuit breaker shut off when the RV power cord was plugged into the inverter, would do the job for only about $400.
And I would like to suggest you look into battery charging via a solar array. The upfront costs are about what a low-end generator would cost, and the 25-30 year useful life with nary a drop of gasoline required, nor a single oil change actually make solar much cheaper than that generator in the long run. If you are at all handy,
this guy's web site and his book can be invaluable.
