We just use the one seat (no choice for us, too many seats/kids). But, McDonalds indoor playgrounds became our favorite! We hardly ever bought anything, just stopped for 10-20 minutes every 3-4 hours to play. It really helped the kids to have somewhere to expend some energy and then they were okay to get back in and go again.
Another thing that works for us is "presents." Every couple of hours, each of my kids gets to open a present. One time, it's a snack, and the next, it's a small toy (usually from the $1 store). They love opening the present and it helps to keep them busy a little longer. They know we will stop every 2-3 hours for potty breaks and when we get back in, they will soon get another present.