@Keitha you will love TCI whether you ultimately stay in Provo or on Grand Turk. I have done both (as well as the Turks & Caicos Explorer) and both are great. I know you would prefer an Air BnB, but I can't offer any experience with that. I can however offer my recommendations on two of the places I have stayed.
If you opt for Provo, I would recommend staying at the
Ports of Call (formerly a Best Western) and diving with
Dive Provo. The dive shop is literally across the parking lot so it is hard to beat the convenience. You will get into a van at the dive shop and they will take you to the habour where you will get on the boat. From there, it is a fairly long (about 45 minutes) boat ride to the dive sites. I was on a package that included breakfast and (I think) lunch, but not supper. This was not a problem since there was a grocery store with a full service hot & cold deli where we could get everything from a sandwich to pasta to a pizza at a very reasonable price. On those days when you feel like something a little nicer, the restaurants on and near the beach are also only a few minutes walk away.
As for Grand Turk, as others have mentioned, it is another airplane ride (a "bug smasher") once you get to Provo. IIRC, the flight to Grand Turk is about 20 minutes. I stayed at a resort called
Bohio, and I highly recommend it. It is run by Tom and Ginnie, a couple of Canadian expats and their family and that is exactly how you will be treated - as family. It is not a cold corporate style resort by any means. Once you check in, you can expect to be greeted by name and a warm smile (and maybe even a hug) when they see you each day. The boat ride out to the dive sites is only a couple minutes, so the surface interval is done back at the hotel. This gives a bit more room on the boat since it will only have one tank per person and the boat crew/dive masters will swap out tanks while you are doing your surface interval. A "typical day" at Bohio will go something like this:
Get up & go for breakfast
Go back to the room and put on your bathing suit then head to the dive lockers and get ready (get into your wetsuit now because you won't have time on the boat)
Hop on the boat and do the 1st dive
After everybody is back on the boat, head back to Bohio for your surface interval and while there, place your lunch order
As your surface interval is coming to an end, get back on the boat
Do your 2nd dive
When everyone is back on the boat, head back to Bohio
Grab the gear that you need to take up to the dive lockers and head up. The crew will bring up (and rinse) your BCD & Regs. Your weights will stay on the boat.
Go to your room shower & change and head to the cafe where your lunch (which you ordered on your surface interval) will be out in a minute or two.
The afternoons are yours to fill as you see fit.
Dinners are not included and while they might seem expensive, I found that they were either big enough to share or to take leftovers home to put in the fridge in the room. (I would order a meal, bring home the left overs and then the next night, I'd bring the leftovers back & they would reheat them for me.)
As for the diving, it will be pretty similar whether you are diving in Provo or in
Grand Turk. It will be walls starting at between 40 and 70 feet for the most part and do not be surprised if it is relatively "sharky", although I found diving near Provo to have more sharks than Grand Turk (Grand Turk, however had more turtles than I have ever seen!).
I'm not sure where you live, but if you are near the GTA, I would STRONGLY recommend going to the
Toronto Outdoor Adventure Show later this month. I know that Dive Provo will have a booth there and Bohio usually does as well. If you do live near the GTA, both Air Canada and WestJet offer non-stop flights from YYZ to PLS.
TL;DR: I loved Provo, but I would go back to Bohio in a heartbeat.