B1 And Travel Restrictions
 

Hi, my cousin was granted a B1 (multiple entry) visa. He intends to remain here for 2 weeks and then return. For week one, he will be attending a business conference. On his second week, he would like to go on a cruise visiting St.Thomas (U.S. Virgin Islands) and San Juan (Puerto Rico). Can he do this, or are there any travel restrictions - if not what documents may be required. Many thanks in advance!