The answer to your question really depends on your personal spirit of adventure and comfort traveling on your own in foreign lands. I cannot comment on Ponta Delgado (never been there) but all of your other ports can be done on your own at relatively low cost. From Civitavecchia you can take the free shuttle bus to the port entrance, walk 4 blocks to the train station, and buy a 9 Euro BIRG ticket which gets you round trip train to Rome and all day use of Rome's metro and buses. As to Marseille, there are plenty of options depending on whether you want to stay in town, take a train to a place like Aix en Provence, or perhaps rent a car and drive yourself to various places in nearby Provence. Barcelona and Lisbon can easily be done on your own with the help of a decent guide book.