Another option would be to use solar panels to charge a trolling motor battery. Do not use a car battery, it won't work for long at all. The marine type batteries are not true deep cycle batteries but they are good enough. A friend up at deer camp uses cpap, and I bring a "normal" sized 24f type marine battery. Fully charged, it will run for 3 nights (without humidifier). With a 10 amp battery charger, we can recharge it in about 3-4 hours of running a generator. But using solar would be cheaper and quieter. For $150 on sale, you can get a 100 watt solar panel set from Harbor Freight. I have one for my travel trailer, works great. That should more than keep up with recharging the battery. Lots of sun at Camp Scholler.

If you do go with a generator, pay attention to the loudness specification. The smallest 1000 watt Honda EU1000i, is 42-50 dB(A). That's extremely quiet. It costs about $1000. There are others brands that are nearly as quiet for $500-600. You want an "inverter" type generator. Please DO NOT buy a $89 generator from Harbor Freight, it will be 92 dB and will annoy the cars driving down US 41, not to mention all the nearby campers.