I use wide masking tape across the tread to determine appropriate loaded and unloaded inflation pressures. When the tape wear is biased slightly to the middle the inflation is right. This works for me, YMMV.
I do run trailer tires at sidewall max as I've yet to replace one because the tread was worn out. Max inflation means less heat and less rolling resistance.
Max inflation may be right for the TV too. I just never did the research to see if the fuel savings would offset the added cost of getting fewer miles out of the tires.
