SATURDAY Hike the Florida National Scenic Trail, registration 8-10 a.m., Gold Head Branch Park, 6239 Florida 21, Keystone Heights. Walk at own pace up to 12 miles. Leave trail at 4-, 6- or 8-mile mark. Bring water, snacks, bug spray, a hat, comfortable shoes and camera. $20 a person plus $5 carload for park admission.