Recommendations for Rovinj and Split and questions about Krka NP

I would wait until the second day in Split to go back to Krka. I used the Lozovac entrance, and it was very easy. At the bottom of the falls there are lots of food options and picnic tables. It's a great place to stop on your way around the park. You could stop in Sibenik after Krka if you want, there's not a lot to see, but it's a cute little town to walk through.

It’s a long drive from Rovinj to Split. I would go to Krka the next day. We were just in Šibenik this past August. We had been trying to visit for a while cause I was curious about the city. It was okay, nothing special like Split. I wouldn’t visit a second time. If you do go, there is a parking lot near the bus depot.
You could visit Trogir after Krka which is a cute, very small town, and completely flat.

As noted, Trogir is a nice place to stop, but it is so close to Split that it won't really
give you a mid-drive break. However, if you find yourself with some time to kill,
you can stop and know that you're less than a half hour from Split.

I would agree that Krka is worth more time, especially if your travel plans do not
include Plitvice.

Thank you for the comments.

Any suggestions for a good place to visit between Rovinj and Split, that would be worthwhile to visit but not too far out of the way?

Zadar is a nice little city and flat. You can park right outside the main gate.