A second to the recommendation for Dennis. My daughter and I took the cavern course with him two years ago, and it was easily the best (and also the most demanding) SCUBA course I have taken to date. TSandM is correct; what I learned in that course has affected all my my diving, very much for the better. I stayed at the Barcelo Maya Palace during the course, and it was very convenient. The cave bug does indeed lie in wait in those caverns, but the cavern course (at least the way Dennis teaches it) will also begin to give you an idea of what you don't know yet (even after taking the course), and the committment required to take that next step. Like you, I am too far from the caverns and have too many other responsibilities to take that step - yet.
A year later I revisited the area and spent a week with Klaus as my guide diving the cenotes. Klaus also deserves a great recommendation as a guide - it was a fascinating and enjoyable week of diving! My buddy was unavailable to dive with me, and I was unable to contact Dennis - Klaus was a great choice as a guide. PM me if you have any questions.