Leaving Anastasia SP, head into St. Augustine and turn right at the foot of the bridge. Follow South Castillo Dr. around the fort and turn left at West Castillo Dr. At the end of the street, US 1, turn right.
Proceed northward. US 1 is a good road up in these parts with few traffic lights and little traffic. Just past Bayard turn right on the I 295 / CR 9A bypass around Jacksonville. Again, a good smooth road with very little traffic at mid-day.
An alternate is to go up A1A and take the Mayport Ferry, then continue up A1A through Amelia Island; this time we weren’t planning to stop at Little Talbot SP, Fort Clinch or anywhere on Amelia Island so it would’ve been fiddling around for several hours with town traffic for no real purpose.
After about 20 miles or so turn right on US 17. Smooth road, no traffic. After another 20 miles or so turn right directly onto I 95; this a short jog that dumps us off at the front gate of the Kings Bay sub base and on the road straight to Crooked River SP. From I 95 take the exit to St. Marys Rd. and follow the small brown signs to the park. You basically go to the sub base gate and hang a left.