Genset carb upkeep:  drain it and/or exercise it? Both?

I do both. Engines that are lubricated by oil dont like when all the oil has months or years to drip off the parts.

In terms of gas there is no ethonal free around here. Every couple months I add a gallon or 2 of fresh treated 91. Goal is to add just enough to exercise the genny.

I've even used a siphon hose down into the trailer gas tank to remove as much old gas as possible. I was able to get about 4 gallons of old gas out my tank after the generator turned off from lack of gas.