How do you verify the gas from the stations you stop at now?

The most thought I've put into it when I had a VW TDI was to fill up at a stations that were busy and more likely to have fresh fuel. A brand name station isn't a guarantee that the fuel is fresh if it is on the road less traveled.

That's a fair question to ask but I have some close friends working in the Petroleum industry and they insist on only getting gas from Chevron and Shell from the insider information they have. Not sure if it means much at all though.

Probably not. The gas from many other stations will come from the same refineries. And gasoline is not that perishable, I doubt that the car minds if it has been at the station for 1 week.

The QuikTrip chain in the South has signs that say they have "guaranteed gasoline". Apparently this means it won't hurt your engine: https://www.quiktrip.com/gasoline - but I like to think it means that they're guaranteeing their product is gasoline, because I'm easily amused.