I bought a 2-pack of Costco stadium seats (one for me, and one for whomever - spouse, grandparent makes it that game) that has done super-duty in multiple states over the past few years. Suspends you comfortably off the cold bleachers. Dries quickly since we often play in yuck. https://www.costco.com/cascade...oduct.100476320.html
Love it for all but air travel, so I also have a super-light cushion with a handle from DSG that we use for those trips - no back support, but absolutely fine for air travel and super-easy to pack in a carry on. They sell these just about everywhere, plain or with just about any team logo you may want.