Wnat on earth are you trying to accomplish at the end of the day by having so many energy conversions and why are you using a relatively-poor-efficiency gasoline generator as a power source and why are you proposing a storage medium that contains such a trivially small amount of storage?
If you're trying to supply power to your campsite and your load is that small, buy a smaller generator and forget about storage.
If you're trying to supply power to your campsite and your load is intermittent and you want to save fuel while the load is switched off, buy an inverter generator (lets the engine speed be independent of the AC frequency) and forget about storage. (I have a Yamaha EF2000i inverter generator that I use at the race track for exactly this purpose. Off the shelf ... no shenanigans ... warranty ... starts one pull every time ... no hassles no headaches)
If you're trying to supply power to your house off-grid, you need a much more efficient energy source, probably tied to a bank of batteries, feeding an AC inverter to the household 60Hz AC loads.
If slowing the generator down isn't enough and you really want to switch it completely off, you need a much more serious energy storage system.
If this is a back-up generator for emergency use only as a substitite for when your windmill and solar aren't generating enough, see above; just have the generator charge the batteries when it's running and switch it off when they're full.
The amount of potential energy stored in your grandfather clock is trivial and insignificant compared to what you actually need.
What am I missing by attempting to be completely practical here, by using bits and pieces that you can actually get on the marketplace and are adequate for the task and are proven to work?