I have seen on e-bay an adapter to mount on a push mower to hook an altenartor for 12 v power. It looked like you just remove the blade, mount a pulley in its place, mount the bracket with the alternator, put on the belt and you are ready.
I do not remember what I was searching for when I ran across it, looked pretty simple in design.

Good luck!

 

Hello all;

I have been looking into the generator situation for my fifth wheel lately and have come to several conclusions. There are several "Quiet" models on the market: The honda mentioned above, Yamaha makes a comparable unit, and a Chinese brand that looks and performs identically to the honda. I have been talking to several people with the Chinese brand who have had very good luck with them. The primary differences are the yellow case (instead of red like Honda) and about $250. On the other hand Yamaha and Honda are well established, known high quality products. The Chinese generator, is not as well known but everybody I have talked to has been positive. All three of these generator lines run at aproximately 58-62 decibels, or a normal conversation volume. Something to keep in mind with the "home built" or Construction site generators is that only part of that noise is directly out the exhaust. A great deal of the total noise is also coming through the motor cases and such. A brigs and stratton engine could never be as quiet as one of the above mentioned generators due to no sound deadening around the moter. If you add it, that will remove the cooling.

If you want a reasonably quiet free standing generator, gensets are a different game, buy one of the three mentioned above. I have been doing the homework on this for about 2 months now and am just trying to decide between cheap and proven reliability. That whole cash outlay thing also is a concern.
Sorry about the length, I am just trying to pass on complete information.