I for one do not take Hwy 19. It does add time and IMO the all-interstate travel is really not that bad. I've made it once or twice a year for 20 years (sometimes more often-ugh).
On my route south from Alabama, I pick up I-10 between P-cola and Tallahassee. That stretch is very easy because other than Tallahassee, it's a whole lot of nothin' till you swing south on I-75. Even Lake City has never been bad for me. Gainesville is busy but I usually stay in my lane. If you take the Hwy 19 route, you eventually join I-75 by the time you get to Ocala where I have encountered back-ups and slow-downs at times from O to the Turnpike for no apparent reasons but that stretch is common to either route.
Also personally I like rubber necking on I-75 because between all the pick-up trucks, campers, and rv's headed in both directions, there is always something to look at so the trip feels like it goes quickly.
To each his own. I don't feel like adding more time to my drive when the interstate route is easier for me.
Also, Michael T, some folks pull into the Interstate Rest Stops on I-10 and I-75 and catch a few hour's sleep which is permitted. It's boondocking/dry camping and they do have live security throughout the evenings. I don't do it because it doesn't fit my timetable but others on here do/have. The time of year you'll be traveling, though, might be too warm in the evening for boondocking like that. And since you're asking about campgrounds, you're probably looking for a place to back in and plug in but I thought I would throw that out there.
Bama Ed