lindamat from Portland--During the daytime concerts, you will probably find chairs or benches at many of the stages, (excepting area 3, and the dance barn) and might not need your own, particularly if you're willing to sit on the ground. But for the evening, you will definitely want your own chair or blanket. If you want to travel light, purchase a cheap chair at the supermarkets or drugstores near there.
--Charlie Baum