We have been going to STJ once, and sometimes twice, a year since 1995 and rented all over the island.

I think areas around Cruz Bay are great for a first stay, especially if you like to go out to eat/drink at night. Cruz Bay has lots of options for both and is a great village to stroll around.

In general, water conditions should be good in May. But rentals close to the water (let alone a beach, see next paragraph) are few and far between.

Do your research for any rental that advertises beach/water access, many of them are referring to very rock, no sand access to the bays like Chocolate Hole and Hart Bay (which can be rough).

We stayed in Chocolate Hole and my adventurous mother had no problem rock scrambling to snorkel but in spots, it could be more work then some people would want.

STJ has great from the beach snorkeling at all the North Shore beaches and from areas of Coral Bay as well.

What is your budget? Our group is larger but I do have some smaller houses bookmarked. There are lots of rental options that have pools and great views.

If you are a reader, the Feet, Fins and 4WD book is a great reference for describing all things STJ and the beach and snorkeling descriptions are very good. Even after nearly 20 years, I still refer to it.