First of all, congratulations on your big plunge. And may I also congratulate you on the choice of going to Tahiti - these islands are really as pretty as has been described by many, and the waters are incredibly blue and clear - just like Blue Corner in Palau on a good day.
I dove in Fakarava in 2005 and 2006, some land-based, and some liveaboard, when the Tahiti Aggressor was still based in the Tuamotos doing the Fakarava to Rangiroa runs.
Air: I flew BOS-LAX, then on to Air Tahiti Nui. You may need to overnight in Papeete before flying on Air Tahiti to Fakarava. Unless you're willing to splourge, stay in town at either the Hotel Le Mandarin or the Hotel Tiare-Tahiti - they're in the $100-150 range - and save your money for the Maitai-Fakarava, which is going to gouge you out of a few chunks of flesh.
You could drive around the island of Tahiti, which I did (nothing spectacular), or arrange for a tour. But if you are scrapped for time, rather than tour Tahiti, I'd recommend taking the ferry across to Moorea, which is a much prettier island with nicer beaches and either rent a car or go for a tour there.
Bora Bora is supposed to be even prettier (I didn't go there) and a great honeymoon island, but you have to fly there and its' a lot of money for just a day trip.
As for what else to do on the island of Tahiti, Papeete is probably best for shopping - T-shirts, black pearl jewelry, etc. For a decent meal at a very decent price, go to the Papeete waterfront plaza at around 6:30pm for Les Roulottes. Over a dozen street vendors set up here and cook up a storm, mostly Chinese, but a good Steak Frites (Steak and fries) can be had for about $10.
Fakarava is indeed a very flat atoll. The strip of land that separates the lagoon from the pacific Ocean is no more than about 400 ft. wide. December is the start of their summer, so be prepared for the heat and especially the sun. There are also mosquitoes at dusk.
There are two settlements in Fakarava: Roatava in the north and a really small settlement in the south called Tetamanu. There are also two channels - one north and one south - thru which the water comes in and out, and these are the signature dives of Fakarava.
As far as hotels, the Maitai is it - and for a honeymoon, I wouldn't do it any other way. The other option is to stay at any of about a dozen guest houses. I stayed at one called Tokerau Village, fairly new and run by a nice family, about a 5 minute walk south of the Maitai. I had mosquito issues there and if anyone were to stay there (or anywhere else besides the Maitai) I would recommend going to a camping store and buying a mosquito net for sleeping. I used dental floss to hang it up.
The bungalows at the Maitai have ceiling fans. The few people that I met on the Aggressor who stayed at the maitai said they didn't have mosquito issues, so maybe the celing fans keep them at bay.
Down south in Tetamanu, there is a very rustic resort run by Sane and Annabel Richmond. Really nice folks, a really fntastic location with outstanding diving, but it's not the place for a honeymoon. The bungalows are rather basic, no hot water, hardly any lighting, and even tho there are mosquito nets, you will be donating a lot of blood.
As far as diving, I dove both times with Serge and Carinne at Fakarava Diving Centre. Google them and you should find their website. These people are top notch and their boat holds a max of 6, maybe 8. I'm sure that they can pick you up at the Maitai dock.
They used to be based at the Maitai but are now located a few hundred yards north of the Maitai. The Maitai has another outfit running the dive operations now - I have no experience with them.
Like I said before, the best dives are the channel dives with the incoming tide. Sometimes the current will be up to 5 kts. but that's when there is a frenzy of activity with the sharks. The channel in the north is pretty wide so the sharks are more scattered. But down south, the channel is much narrower, so the sharks will be in a denser pack. Serge runs weekly trips to the south in addition to the dives on the northern channel.
In the northern channel, halfway thru the drift, you will come upon what is called the Valley. There is a humongous congregation of fish here in humongous schools, along with sharks patrolling nearby.
The wall dives are pretty neat too, and you might see some other goodies like dolphins and other types sharks besides grey reefs. December is a good time for Great Hammerheads in Rangiroa, and it might also be for Fakarava.
Serge also does occasional trips to Toau, an atoll to the northwest of Fakarava.
Hope this helps.
All in all, you will not regret going there for the diving.