You will not be visiting the city of Ceasarea but rather the national park which is an historical, archaeological site.
You can take a train to Binyamina and from there a taxi to Ceasarea - just make sure to get the number of the taxi so you can call to get the taxi to pick you up to return.
The above refers to Abraham tours. They do have interesting things, but it should be noted that many of their 'tours" are transportation only. The above reference transportation gives you 3 hours in Caesarea. Personally, considering you will want to eat lunch in the middle of that ( and there are some nice restaurants available) I would either rent a car or take the train. I think you need more time.
If you do rent a car, there is an interesting art museum to visit.
I found it by accident one year and while I would't go specifically, if I had a car--I would definitely go. ( not sure how much it cost to go by taxi from National Park)