Any idea on budget and desires?

Do they want to be able to walk to bars and restaurants? If so, I would recommend Gallows Point. It has a pool.

On the beach? Caneel. There are very few STJ rentals with sandy beach, walkable access. My favorite is Kallaloo but it usually books way in advance and doesn't have AC.

What's their tolerance for driving? Cabs don't like to go much past Cruz Bay. If they look over towards Coral Bay, they definitely need a rental car.

Ask them their must haves (AC, pool, etc) and get back to me.

My favorite rental agencies are Catered To and Vacation Vistas. Destination STJ is also good. Actually, there are may good agencies on STJ, it depends on what they are looking for in a villa.