There's not much near Maruba, which is in a fairly isolated area on the Old Northern Highway. There is a village, Maskall, nearby, which might have a room in a local house, but it would be very, very basic. There used to be a great place nearby, Pretty See Ranch, but it closed and is now for sale.
You could stay in Crooked Tree (Paradise Inn and Bird's Eye View Ldoge are nice, low-moderate priced places) or near Orange Walk Town, either of which would be maybe an hour away by car.
When I was at Altun Ha a few weeks ago, I did see one place on the spur road that I recall was offering rooms in a house, but I don't know the name or contact.
Should be little rain in January. Weather will be about like South Florida.
As I noted in a separate message, you might also think about the new spa at Chaa Creek. Not quite as "exotic," but run more like a professional spa. And lots more to do around Chaa Creek than around Maruba.
Belize First Magazine http://www.turq.com/belizefirst/