You can do that if you want - there are ferries to just about every island as on some of them that is the only way to get there. May have to go a roundabout way to get where you want to go as there may not be a direct ferry. Just have to book hotels in each island and you'll definitely want to give yourself time to visit each island. Great vacation if you if you have the time and money, that's for sure!
Travel Agent/Cruise Specialist w/13 yrs exp and 48 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!