Book with cruise line???

More assured vendor selection, insurance, etc. Price likely higher (the cruise line is a profit making business, as are travel booking agencies).

Tours vs "do it your self drive" depends on Your skill.

Less time required of YOU to research choices. Some may only be available thru ship, then many are not available thru ship at all.

Modest chance of very regretable results if YOUR rental car or ventor has a breakdown and you miss the ship. Few people are ever left behind, those that are definately made the wrong choice! YOU will be blamed, forever!

Feel lucky?

In Port for hours more that you plan to be gone, or overnight, then booking on your own, really takes the "left behind" out of it.