Bonaire is a good suggestion. As is Buddy. Except that as a single, you'll pay a large single supplement. To dive a lot requires you to shore dive - Buddy only runs 2-3 boat dives per day. Most people do on Bonaire anyway - it's the undisputed shore diving capital of the Caribbean - probably the world. There's better than 70 named dive sites within about a 5 mile stretch.
The standard dive vehicle is a 4dr. small pickup so many people have room for one more. I think I was asked 3-4 times at different resorts if I needed a buddy while waiting for mine. It's very low current easy diving once you get over the ironshore at the waterline - the reef parallels the shore at most sites. At many we used the truck as an exit locator - at many of the south sites it's the tallest thing there.
http://www.shorediving.com/Earth/ABC/index.htm
Other options on Bonaire for a single are the Dive Hut, Divi Flamingo, Habitat Bonaire or possibly the Plaza Resort - the only true All-Inclusive dive resort there. Most bundle diving/accommmodations/truck rental and often breakfast. Just about every rental property has a dive pkg. deal with someone.
Another option if you're willing to risk hurricane season is Cocoview on Roatan. You'll dive on the same boat all week so pretty much have buddies right away. It's as good, maybe better than Bonaire - probably easier to get to and they have a shore dive off the resort that includes a large purposely sunk wreck. The top is around 25' the bottom maybe 75'? CCV has a $200 single add-on but it's
really popular so you may not find an opening.
Anthony's Key Resort is another option - dive with the Dolphins there - at 60' on a flat bottom it's within your skill set. They do multiple boat dives per day - 3 IIRC plus 2 night dives and there's a so-so shore dive off the Key.
Reef House Resort is a more remote option also - IDK much about it. Another option is one of the more than 1 dozen shops on Roatan's West End - there's all sorts of affordable housing from Hostels up and you don't need/want a car - everything is accessible on foot or via a cheap cab ride. I like/recommend Coconut Tree Divers but even if you find something else, the Roatan section of their website contains a lot of useful info on that area.
If you choose CCV or RHR you're mostly going to dive there/stay/there/eat there all week. There's nothing nearby and CCV is on it's own island. AKR at least is 5mins. by cab to the West End if you're looking for nightlife - or other food options. The AI's also have a shuttle service to the airport so a car is not needed. On Roatan it's not a good idea anyway due to liability (yours) if you hit something.
One other option is Sunset House on Grand Cayman. It's a mostly inclusive resort - they bundle room/diving/breakfast in their packages and there's several shallower shore dives just off the resort. Mostly divers stay there, are at My Bar there etc. It's a few minutes walk from downtown Georgetown for other dinner options also. Earlier this summer they were offering a single deal at the same price as their economy double rate - garden view rooom but all the diving etc. was included. Maybe they still are.
Grand Cayman is very expensive though - if you found a buddy you could do about 1/2 dozen other easy entry shallow shore dives as well, Eden Rock/Devils Grotto, Turtle Reef, Lighthouse Pt, Cobalt Coast all start shallow. Turtle Reef IMO is about the best and it's 40-50' to the sand there. You'd need a car to access those sites - be cheaper than a cab.
Really the
most diving you can do (without repeating) is via a dive liveaboard. We average 25 dives/week - I've done 27. They typically move the boat twice per day and the last dive is often that day's night dive so you get familiar with it during the day. You'll have a buddy in your shared cabin-mate and on most that I've been on single divers get adopted by the group the 1st day. It's a pretty small boat for a week so most people are very open. We've dove liveaboard dives as 2, 3, 4, 8 and once 11 people. My last two we dove with a third person we met on the van/boat most of the time.
There's multiple options but some popular ones are Explorer Ventures or the Aggressor/Dancer Fleet. Another option for you might be one of the Bahamas boats - everything from Blackbeards at <$1000 to Aquacat or Carib Dancer. One other advantage to a liveaboard is that a DM or other crew member is always available to dive and guide - at no additional cost - except maybe a bigger tip at the end of the week. We tend to do our own dives but on our Explorer trip one of the crew led just about every dive for a family onboard.
Some links to check options and avaiability:
Explorer Ventures: Adventures in Liveaboard Diving! -
Availability
Aggressor and Dancer Fleet -
Availability
Many of the Bahamas boats book direct. So under Dive Liveaboards are links to most of them:
Bahamas Government Portal - BDA Members
One last consideration from your area is look at travel times. If you start looking at Thailand or Indonesia that's going to be two days travel each way. Even Fiji is 14hrs. from LAX - my buddy just did the Dancer boat there last year.
Contact a couple of dive travel agents also - they often know who is currently waiving their single supplements.
Caradonna is one I've used/trust.
hth,