Oh and as for the real question about training etc, I don’t know. I’m sort of in the same boat re: not wanting to do intervals/structured training/stop eating pizza etc. but wanting to ride better. But I think I’ve sort of exhausted what I know/can do on commutes without reading up more on it. Boo. Effort.
I would say, very generally, based on my limited (in)experience/(un-)knowledge, that the more intensity you ride for longer the better you’ll get. But that doesn’t include building up endurance. Any rides past 60 miles are rare for me.