You can take the Ferry or Airplane to Vieques I took the Ferry from the town of Ceiba not far from my Home. My experience at the Ferry Terminal was great no chaos I did go in the month of August this is not consider a Summer month in Puerto Rico perfect to go and visit Vieques.
When you buy your ticket online you will see that they charge for whatever you will bring; Chairs, Umbrellas, Beach Coolers, ect.... those items are not high to pay. What is high to pay is the Rental Car. You can bring a bike or your car to Vieques.
Vieques have a cargo ferry and a people only ferry I took the cargo to Vieques and the only people ferry to Ceiba. The cargo is more small but you will not feel any waves. The big ferry for only people have a beautiful view to the ocean and have two levels.
The people that lives in Vieques have priority to board and leave or to be seated.
I visit the Public Plaza and do a prayer on the Church La Inmaculada Concepcion this church was built in the year 1844.
I was so happy to see above the Virgin Mary our Puerto Rican Beato Carlos Manuel, you can see it better in the next photo. His love for Jesus was so big that he remembers in this beautiful Stain Glass asking Pray for Vieques.
You can read more about Beato Carlos Manuel on my Youtube Video from the Cathedral of Caguas that his remains are there also a Museum.
Also if you are Catholic is a beautiful Church to get Married. I also recommend the The Blue Horizon for Weddings.