This city is VERY easy to see on own
just get a guidebook,,,can walk right to Palace from port(few blocks only),,,lots to see and do and then pick and chose what you want to do after.
We were there 6 hrs...and barely got to see it all.
There is a tour bus(sort of HOHO) that is at dock area(not sure of times,but can google) that will also take you around.But most of city is pedestrian only,,,but some like it to see outskirts of city.
Also,,google tourism in Split and you can see how compact it is (Old town) ...LOVED this city and wish I d had more time there.