Well you might have me beat in the number of states, but I transported race cars in rigs for close to 15 years. IMO you are quite exaggerating. BTW, All of the big rigs with Cummins, Cats, refers, etc. ALL sound different. Never met a trucker who was so highly attuned that he could tell the difference enough to wake him. I also suggest YOUR cab/sleeper was really insulated poorly. Try a newer one. (less than 20 years old
When sitting in the sleeper with a reefer or drive motor idling, you CANNOT even hear the truck, genset or reefer next door.
A "loud" Generac idling is not near as loud as a big Cat, Cummins, etc. And if you read the thread you will see that most agree with me and did suggest that he pick a spot of least interference..
As far as noise level I would be happy to give you some db level readings from lots of different units...