Even though our new TV is a gasser, I would still do it... RPM is directly proportional to generator noise... Slow speed gens have drastically less valve noise, less cooling fan noise (even better if it is a liquid cooled genset), less vibration...
We met a couple in a real nice DP in Worthing State forest a few years back, it was like the first weekend of April. Deleware River was still in breakup and we were one of three occupied sites in the park... Wide open grassy area... Was out with the DW and DD's for a walk after dinner and stopped to say hello. Spent a half hour with them, and never realized that their genset was running... Only thing that gave it away was the crockpot of meatballs they were offering a taste of... This thing made my Honda 2k sound like a generiac...
Went back the following day to check it out further... It was a 8k Kubota liquid cooled diesel 1800rpm... Ran the whole coach with 2 ac no problem... Literally could not hear it from 20' with no other noises around.
Your idea of marine tank is same as I have been visualizing, but not sure about fuel buddy... I tried once to get one of those in the truck alone... No fun. I would be more apt to do two or three tanks and swap them when empty... Still gonna be 50lb each.