Vacations can be fun, but you know when I look back on my childhood, the memories I cherish most aren't when gobs of money were being spent to go on holiday, but were those times when my parents set aside time to spend with me, and the backdrop of the activity wasn't so important. However, at the time I naturally looked at the fun things my friends got to do, and if I didn't get to do them, then I felt that life was totally unfair.
I hope you and your kids have a great time in the park, and it becomes a cherished memory for them when they later look back on their childhoods. Kids need to be able to let off steam, run around and have fun, without constantly being told to be quiet. I will admit I don't particularly enjoy the sound of children fussing or fighting, but the sound of children having fun is music to my ears and I would never ask them to be quiet while they are having fun.