Where is the toughest stadiums to perform as "visitors"?

ANYWHERE until at least early October.

I would hope that the answer would be "nowhere". After all it is h.s. football and h.s. band, not college arenas. Any adult in the stands knows that whether the band/football is the home team or the opposition they deserve to be shown good sportsmanship.

From my experience, my band has never encountered any problems at visiting stadiums.

Most crowds will be very courteous to the visiting band. Except at Floyd Casey last year when Lake Travis beat Longview in the state championship. LT's cheerleaders made fun of Longview's majorettes and the football team ran onto the field while the band was still marching. That was absolutely classless and disgusting on Lake Travis' part. Especially when Longview's band always patiently stands at parade rest while the other band is marching.

I think they're right, it's not a competition as is the football game, even though both bands really want to do their best to out-do the other, band parents and their fans at most places are very respectful and appreciative of the other bands.
I would pose the question opposite, which place is the greatest place to play as a visiting band? Facilities, seating, logistics, laison to the other band, concession bennies, crowd appreciation, you name it. Who makes you feel welcome?

Maybe I could ask a second part to that question. who has the worst field that you have performed on and why?

Physical condition, 2 years ago in Mount Vernon. It was just really torn up from the game.