re: OB Builders....Have you ever built a box/house over your generator

I would build an enclosure with a good suction fan and back louvre to pull air hard across the unit, and an exhaust connection. Make the louvres like an attic vent, make the enclosure look like a little dog house or lean-to kind of thing.

Will be a haven for black widows and other assorted bullshite

I would make two whole opposite sides louvres, one side with a good strong fan blowing air out

A trick with gensets is you want the air flow to be forced from the back of the generator to the front of the engine, it helps keep the generator cool. If the generator has a cooling fan though, make sure you force air the same direction across the generator that it's fan does so you aren't fighting it.

Also, keep in mind you'll need to be able to fill the gas tank. Don't frick that up by making the roof too low. Alternatively, buy/build a substantially larger tank, put it in the "attic" and put a full neck to it outside.

This can easily get as out of hand as you'd like it to be. I make engines run indoors for a living, we can engin-nerd this to death