He can’t leave Florida, whether or not DeSantis fights extradition.
I think as a practical matter, Trump can travel to any other state with a GOP governor, as under the 14th amendment to the US Constitution it is the governor of the state where the indicted person is located who has to go along with extradition in order to make it happen.
I don’t think Trump can trust the Secret Service any more, as they answer to Biden, not to Trump. De Santis will have to assign Florida Highway Patrol to protect Trump from being kidnapped and taken to New York against his will.
Trump is not going to run away or avoid this. Trump said long ago, he’d turn himself in or tell them where to come get him.
This is a DeSantis stunt.