I have made that same trip more times than I can count and the attached photo is the
fastest way I have found...hands down.
301 will show up on most GPS' as
'the fastest,' but there are so many traffic lights, and often traffic (not to mention speed traps), that it ALWAYS turns out 30-40 minutes longer than the original estimate on the GPS...and you can literally stew in frustration watching your ETA change regularly.
The route I'm showing, takes you through Ocala National Forest where there is a wide two lane, with lots of straightaways to pass if you're unfortunate to get stuck behind a slower vehicle.
To keep from being fooled by your GPS and if you're not familiar with the route, go over to Home Depot on 441, first plug in Salt Springs (make sure it's showing Hwy 25), then Palatka, then St. Augustine to get you to I-95.
Once going north on I-95, punch in Kingsland, GA (making sure that it shows the I-295 loop around Jax and not I-95 through downtown Jax).
I guarantee that 99 times out of 100...this will be your
fastest route.
Have a safe trip.