Author: Tim S (---.ei.psu.edu)
Date: 11-05-14 09:00
1) Private cars can be taken on the cargo ferry. But, and it's a big but, freight gets priority as well as local Culebrenses. And the cargo ferry is usually fully loaded, leaving little room for the cars of non-local visitors. In my opinion, it is not worth the risk. Better to rent a vehicle when you get to the island.
2) I'm not sure how the ferry service has been running lately. Some one else may be able to answer. You may find that how it is running now is not a good predictor of how it runs tomorrow or any other day after tomorrow.
3) I'd say get your tickets online with the link Micheal provided. http://www.culebraferry.com If you opt for a driver to take you to the ferry, ask if they will get you tickets in advance. Some will.