Microwaves and generators
Actually, most modern microwave ovens are not the biggest power consumer you will use a genset for.... the overhead refrigerated A/C is the big power hawg, and will load the struggling generator the most. Microwave ovens will pull no more than one Kilowatt or so, and some will even run on a medium-duty (700-800 Watt) 12 Volt DC - to- 120 VAC inverter. If you don't need refrigerated air in the back, consider one of the inexpensive portable hand-crank (or what I call "Heart-Attack-Start") gas generators (available from Target, Sam's Club, and others for a few hundred bucks for a HUGE one),
or better yet, get an 800- to 1000-watt inverter to allow you to run a medium to small microwave from your existing vehicle 12 volt system.
I use my inverter for operating all sorts of household products, from shavers to electric drills and soldering irons, TV's and video players, etc, inside my RV. My microwave is a bit too big for this size inverter, though, so I have to fire off the generator OR plug into AC outlets outside to run it.
I just went through the process of rebuilding my Onan 4KW genset alternator, and it was EXPENSIVE. Cost me $500 just for the alternator stator, $250 for a regulator block... and now it needs new crankshaft bearings in the engine. No one seems to sell non-OEM replacement parts for Onans. I own 2 other generators, a small 500-watt Coleman and a 4 KW heart-attack-start emergency generator to pump water at home when the power goes off (we live in rural NM). The Onan is very quiet and smooth, AND has electric start.
Even at that, it is difficult to sleep (for me and my RV neighbors) when it's running. I'd hate to think what life would sound like if I tried using one of the almost-unmuffled one-cyliner pop-pow-chug-chug generators in the RV except for emergencies only. Onans are the only ones I've been able to find that run smooooooth and relatively quiet... they PURR instead of ROAR. But it COSTS for such smoothness.
I failed to find even a USED Onan for less than a thousand bucks on Ebay... and there are quite a few for sale there. But they cost a lot more new, and are worth a lot even used....