Now that he is in high school, I just show up :-) I do keep a folding chair in the car incase I don't feel like sitting in the bleachers.
In my son's early days of travel ball, it seemed we packed everything but the kitchen sink - popup cover tent, cooler packed with drink, water, snacks, etc, folding chairs, bags of dry snacks (chips, crackers, etc), his equipment bag, luggage if a tournament requiring overnight stay, etc.
Over time I simply got tired of dragging so much stuff around. By the time he was playing HS (last year of travel was his sophomore year), we only brought folding chairs and a small cooler with water/drinks. Brought some extra cash to purchase burgers, BBQ, fries or whatever from the booster concession stand (yes, even when we were the visitors). If the forecast was for a very hot day I'd bring the popup - but most HS games were in the evening.
Now that he is playing at the college level (D2), we don't even bring the chairs unless I know for sure we'll need them - the home field is also home for a Single A Affiliate. Just cash for the entrance fee and concessions. It's nice to just enjoy the game without worrying whether we forgot something.