All the four small atolls in the group are uninhabited: Matureivavao, Tenararo, Tenarunga, and Vahanga.
Accommodation can be booked from this site 
Names of families offering online booking:
CHEZ BIANCA ET BENOIT - Guestroom
CHEZ JOJO - Guestroom
PENSION MARO'I (highly recommended) - Family Pension
TARA ETU KURA - Family Pension
There are no ATM's or banks. Please bring enough French Polynesian Francs for your holiday. Locals here deal with cash only. You can exchange USD/Euros for French Polynesian Francs at the post office in Rikitea. The pensions sometimes accept credit cards (ask first).
Knowing French or Tahitian will serve you well here. Very few locals speak English. At the pensions usually one person will know basic English words, but anything approaching a conversation will be impossible.
Flights once a week from Tahiti flying Air Tahiti (http://www.airtahiti.aero/home.php).
Flight number VT951 leaves at 0540 and arrives at 1105 and the flight back on the same day is from 1155 and arrives at Tahiti at 1450.
Once at the airport you will need to catch a Taxi boat to the city Rikitea.
There are no rental cars. Arrange with your pension to be picked up at the dock (after taking the ferry from the airport on the motu). The island's 16 mile circle road can be walked in 4-6 hours. It's a great walk. If you wish to see one of the other islands in the group, ask your pension about day trips. Pension Moroi offers a great day trip to see several other islands. It's a fascinating day.
Rikitea Ruins At Mangareva's main village, Rikitea, visitors will find a number of ruins. Among these archeological relics are a convent, a triumphal arch, several watchtowers, a prison and a court. These abandoned remains have been noted for their dark, eerie feel.
Rikitea Rectory Across the path from St. Micheal of Rikitea Church is a well-maintained 140 year-old rectory, occupied by the parish priest.
St Michel of Rikitea Church Constructed of fired limestone, this neo-gothic Catholic church was built under the auspices of Father Honoré Laval. The church, which is still in use today, is inlaid with iridescent mother-of-pearl.
Enjoy a piece of the planet nearly untouched by the modern world. The lagoon is stunning. Tour a black pearl farm. Spend a day on a motu having a picnic, tour the atolls historic churches, hike around the entire island, or to the top of Mt. Duff. Snorkling is quite good, if only there was a dive operation. Watching the stars at night.
There's 1-2 restaurants in Rikitea. You can also eat at the pensions (let them know ahead of time as they only prepare enough food for those they know are coming for dinner). Food at the pensions is simple, tasty, and plentiful. You will not go hungry. The hospitality is heartwarming.
Despite French nuclear testing at nearby Muraroa the water is safe to drink, and bottled water is available from small shops in town. Many of the locals, the land, and water have been tested for residual radiation. All came back clean. These tests were performed by Greenpeace. Furthermore, all water is rainwater collected by catchment from roofs. There are no streams/wells.
In Rikitea there are 2 small markets. One has a decent selection of alcohol, but you will pay dearly for anything but beer. A bottle of Absolut Vodka was priced at nearly $100USD. If you wish to have anything specific for you trip I would highly recommend bringing it with you from home, as prices even in Papeete are high.
At night the pensions, and a couple of small restaurants, serve beer (Hirono).
The locals are friendly and a delight. Wear lots of sunscreen, and be careful of Stonefish. Bug spray is recommended. Europeans, and to an increasing degree North Americans, are less modest than Polynesians. Dress appropriately. I would discourage any public nudity despite the idyllic setting.