Being on St. Croix was...interesting. The island is mostly poverty-striken. The people were basically nice, but we stood out like a sore thumb. We ended up leaving. I wouldn't recommend St. Croix.
Roosters run the streets and wake up before sunrise, and regular and hermit crabs are seen all over the beach. You are not allowed to take any shells, coral, or sand. They ask you at customs. I had a piece of coral in my suitcase, and I am certain that they removed it in San Juan.
Most of the activities are outside, so if it rains (as it had most of the time I was there, so no tan) there is really nothing to do but spend all day in a bar (or walking the streets with open booze), which I didn't do. The rain made laying on the beach a no-go, and affected the sunrise at Point Udah (the Eastern-most area of the United States, so we got to see the sunrise first). We were able to see a wicked sunrise before the sky lit up.
There were two interesting forts in Christiansted and Fredrickstead.
We went snorkeling on Buck Island, a very beautiful place - the water was turquoise. There were many beautiful structures there, I got lots of photos.
THE POINT (SUNRISE)
For some reason, my website software won't work with videos, so I had to go the You Tube route: