For every beard hair that wound out of Jerry Garcia's round face, there's a band trying to re-capture a bit of Grateful success. With the exception of Phish and, if you insist, Dave Matthews Band, no band has brought Southern-fried, purple-hazed noodle-rock to the masses with as much success as Widespread Panic. Since 1983, the band has been the focal point for legions of fans who, as is the jam tradition, chronicle every note of every concert. Seeing as how these guys are consummate road warriors, that's a lot of tape. And tonight, expect the reels to roll long: Riverfest organizers have given Panic three-plus hours to bring the long-winding choogle to the river.