The Palatka-to-St. Augustine State Trail has been completed. The trail runs from East of US 17 in Downtown Palatka to Vermont Heights west of I-95 off SR 207. The trail is about 19 miles and crosses SR 207 twice: first between Elkton and Vermont Heights with a lighted cross walk and again between two curves in Spuds with a yellow-to-red stop light (Is there a special name for these kind of stop lights?). The trail is a part of the 200 mile River-to-Sea loop and eventually will be connected to Downtown St. Augustine and Flagler County. Official grand opening is April 6th, but is now open to users. To get to the trail from Jax, take the SR 207 exit and head west on 207 for about 5 miles, there will be a trail head just to the west of Vermont Heights using the old section of 2-lane 207.
I grew up in the Hastings area and I rode the trail around Christmas while visiting family. The trail head in Hastings was completed but closed at the time, but the one just west of Vermont Heights was open. Just a few issues I had: the Hastings trail head isn't in downtown Hastings which might have been nice for the town to have, the crossing in Spuds also has an obnoxious amount of street lights leading up to it (I know it's for safety but I can't imagine the people that live there being happy about it), and when they made the bridge across Deep Creek the trees were cut back pretty far from the trail leaving users exposed and missing an opportunity to have a marquee section of the trail. When you'd kayak down Deep Creek, the old rail trestle was pretty over grown and created a good canopy over the creek and rail bed.
https://www.staugustine.com/news/20190117/final-segment-complete-in-bike-trail-between-st-johns-putnam-counties