My wife found a deal on tickets to St. Croix and booked them for the end of March. We have never been and looking for some advise. We have yet to book a room, looking more at condo/home rentals than hotels. It will be me, my wife, 13 yo daughter and her friend.
One option: Google "pink condos st. croix." You will get some links to condos on the west side, which is the calm side, of the island. You will have a beach to yourself with some great snorkeling. There are not usually a lot of the owners/guests staying there. You can see the Frederiksted Pier from there and watch the sunset every night.
I would like to be able to shore dive. Can you shore dive most anywhere? Is a surface float needed? Do most shops rent tanks and lead? Any shops you would recommend or more importantly, any you would avoid?
The Frederiksted Pier is a must, both during the day and at night. N2theBlue's dive shop is pretty much at the end of the pier. They rent tanks/weights and have guides if you want them. Good people to work with. It's been a few years since I've been, but I understand you need a float around the pier. Cane Bay has a wall, but as morecowbells said, it is a pretty good swim out. You could take the family if you shore dive there. You can rent a tank at the Cane Bay shop and there is a nice beach/snorkeling/restaurant.
Also recommend N2the Blue for boat dives. Did I mention above, the west side is the calm side? The west side has a couple of small wrecks. The north side, at least the Salt River Bay area, has generally had more choppy water when I've been there.
This link brought back memories. Dave's pool is still shown as being located at the Scuba Shack (first dove there in 2005 and again in 2007) and even has a picture of the place. By my next trip in 2008, N2the Blue took it over and moved to Frederiksted sometime afterwards. The structure became rundown. Not sure there is even a path to the water at that location now.
If you're looking for other things to do, there is quite a bit of info here on SB. If you can't find it, ask here for what you're looking to find. Someone can probably help you out.