Fans usually work great overnight. Even better if you can find a USB powered one or a 12V.
We do have solar, and it works for most of our boondocking or overnight parking without hookups, but occasionally we'll be in a situation where running the AC is unavoidable. You'd need a couple thousand invested in a lithium battery bank to do it for a couple hours. Or, you can run the generator...
This is why I invested in quiet Honda generators, and not one of the $500 chain store specials...
For just the air conditioner, a single Honda EU2000i works fine, although I do flip the breaker to our converter off. Outside, is barely noticeable above the noise of the air conditioner unit running. Inside, the noise is undetectable.