Eventually I am going to give a vehicle to a family member that lives in Massachusetts , what do I need to do and what documents do I require ? What do I do with the license plates after I turn over the vehicle to him ?

Cancel the registration before you cancel the insurance.

For you, you'll just need to cancel your registration with the Division of Motor Vehicles. You can do that online at www.dmv.ri.gov Choose the Online Services tab on the home page. You will have to consult with the Massachusetts Registry of Motor Vehicles to find out what your relative needs to register the vehicle in that state.