We went for 90 minutes. No backpack. No gear. Just us (and my camera and car keys). They whined and moaned about going. They reluctantly got out of the car when I parked by the picnic area. They laughed and giggled and hollered and ran and hid and jumped and made up some game that I couldn't figure out if I tried (I didn't really try). We got in the car after 90 minutes and I think we all felt really good.