Renting in USVI

[Scuba]

Hello, my husband and I are planning ER in late 2016. We love the USVI's and would like to rent a condo month to month in St. Thomas or St. Croix in 2017. We are thinking of April - June but want flexibility to leave early or stay longer. We have vacationed on STT many times and spent 2 weeks on STX recently. Any advice on rental process, lifestyle on either island, best source for reliable rental vehicle? We will likely spend a lot of time at the beach but would also like to get involved in local community, possibly volunteering, while there. We love diving and sailing, ASA certified but do not own a boat. Thank you!