If I remember correctly from the last time I was there (May 02) The ferry was right at the downtown dock. Which is right, basically at the shopping area. If you have to tender in, you will be dropped off right there at the same general area. If you are docked, you will be at Havensite which is a 5 minute cab ride to downtown, OR a mile-to a mile and a half walk. (I generally like to walk to town from Havensite, and cab back, BUT it isn't a very nice walk. Nothing to see, but a few rundown buildings and thee busy road. I just like to walk! It's not a bad walk for someone who is used to walking. I would NOT recommend this walk for children or seniors! It's right along the waterfront, there are sidewalks, just not much to see, kind of dirty. )
I also have heard that the ferry from CA can get rough, but if you like boat rides, you'll see a bit of St. Thomas from the ocean instead of from the cab going to Red Hook. You'll also go past St. James Is. (which has a giant for sale sign on it) and get a good look at Barbra Streisands house on a cliff! Pretty cool.
Mrsfuzzmo