Well if you have the Onan 5500 you are good. They purr like a kitten. If you had the more common 4K "MicroQuiet" you would be singing a different tune. They are rattle buckets.
The convenience is nice but I will NEVER buy another trailer with an Onan 4K built in.
OP since you don't have a fuel station to tap into I think your best bet would be to go portable. Dual Honda EU2000 models in parallel will power your AC just fine. My brother ran this setup on his old trailer and its quiet. Just have to deal with lugging them around and securing them so as to not get stolen. He sold them when he bought his new trailer with Onan 4K built in and is kind of regretting it.
