If you are keeping the Palmetto and adding Silver Palm, then why not run Palm down the FEC line from JAX to MIA? There is no passenger service south of JAX to West Palm on the Florida east coast. Amtrak and FEC were in serious talks a few years ago about starting up a passenger service on the FEC east coast tracks. You can't get to St. Augustine, Ormond Beach, Daytona Beach, New Smyrna Beach, Cocoa Beach, Melbourne, Stuart, Vero Beach, etc, by train, and that would probably be a good market.
If we want to have enough equipment to also restart service New Orleans-JAX (the "temporarily suspended" east end of Sunset), why not look at (1) extending Palmetto to JAX and running a new service (on the FEC) JAX-MIA, and restarting NOL-JAX, making JAX a connect hub for Palmetto/Palm, Sunset-east, Silver Star, and Silver Meteor, or (2) extend Palmetto to MIA on the east coast FEC tracks. Tampa currently has rail service via the Star's dog-leg, and a bus connection to the Meteor at Orlando to Tampa (with a bus connection down the southwest FLA coast to Ft. Myers as well) and bus connex on the CSX S-line Palm/Palmetto path through Ocala and Gainesville. I would frankly expect a higher passenger count from an FEC east-coast run than whatever you might gain from switching the interior Tamp-Jax S-Line bus back to a train.
To add significantly into this equation, central Florida is currently working on a north-south A-Line commuter service that will run from Amtrak Deland down to just south of Amtrak Kissimmee (Poinciana). This commuter startup will also involve rerouting most CSX freight from the A-Line to the S-Line, (adding to the existing S-Line CSX freight traffic) making the restart of a Palm S-Line service more problematic, and with all the commuter train traffic that will be running through the A-Line Orlando corridor, adding a third Amtrak train through Orlando (actually a fourth through that corridor, since Auto-Train at Sanford will also be in the new commuter corridor from Sanford north to Deland) would also be a problem. I am already wondering if they will want to build a new, elevated rail bridge over the St. John's River at the north end of Sanford, given the much greater frequency of train service that bridge is going to see, plus of course that is a single track bridge, and I think they will try to double-track the entire corridor (a good bit of that corridor already is double). Complicating the idea of a new rail elevated bridge is the fact that they just recently finished a new wider elevated I- 4 bridge over the St. John's River and the A-Line track goes under that and then makes a 90 degree turn just before it gets to the existing rail drawbridge, so they might have to re-route that entire track section to do a new elevated rail bridge.