I've never been to Royal because the descriptions I've read have sounded a lot like what you wrote, but I've been to Troy many times, mostly to practice skills in that 70-ft bowl. A nice little dive, with the remains of a Civil War-era paddlewheeler in the spring run.
Troy Spring State Park
This 70-foot deep, first-magnitude spring offers opportunities for swimming, snorkeling and scuba diving. A hidden gem in north-central Florida, Troy Spring has picnic tables, an interpretive nature trail, and a riverside dock for canoeists and boaters.www.floridastateparks.org
Troy is a state park so solo is a no go.