Hi Beth & Scott,
We've been to Xcalak a few times.
We just got back from a wonderful stay at Casa Carolina last month. Caroline and Bob are very gracious hosts and we'd highly recommend them. We try to visit somewhere different each trip and we haven't been disappointed so far staying at Casa Carolina ,Tierra Maya or renting Nuestro Tesoro (I think the name has since changed).
Been meaning to write that trip report
You can spend time doing as much as you want, or as little as you want in Xcalak. We chose just to relax this trip and it was fabulous. The starry sky on a clear night is the best we've ever seen.
The beach can vary in different areas. Some have larger amounts of turtle grass than others, but that's a good thing, for the aquatic life. Most accommodations provide access to kayaks or have piers for your swimming and snorkeling enjoyment.
Diving is excellent in the area. If conditions are good, a dive trip to Chinchorro can be arranged.
A few places also offer boat trips to Belize which is a very fun day trip. I think the boat ride through mangroves and Chetumal Bay was about an hour or two each way to San Pedro. Local tour guides also offer trips for bird watching and of course the famous fishing. We haven't fished yet, but people often talk about the Grand Slam which I think is a tarpon, bonefish and snook?
The Leaky Palapa serves excellent food and is open seasonally. There are a few other dining options open year round, El Caribe comes to mind, all serving good food and they offer some nightlife as well, even if it just involves conversations about that day's fishing or diving.
Xcalak was spared from the severity of Dean, but a day trip to Mahahual is an easy drive and I'm sure the folks up there would welcome any tourists until the cruise ships start up again. Laguna Bacalar, Cenote Azul and some small ruins are within driving distance if you want to make Xcalak your travel base.
Hope this helps.