We did not lodge here, but went on The Black Hole drop excursion through Ian Anderson's. It is ONLY offered through them since the sinkhole is on their property. Their website gives a great overview & photos.
There is a minimum of 2 people for this excursion. My only complaint is that we had to PREPAY with a credit card -- which meant I received an international fee/charge on my credit card. I wish they would have let me pay in cash when I arrived. Nonetheless, the staff was very helpful at answering all of my many questions beforehand & Rene in particular was very prompt at responding to emails.
We stopped by Ian Anderson's a day before our trip just to confirm. I forget the guy's name who is sort of the front desk staff/first point of contact, but he offered to give us a tour of the lodge in case we wanted to stay there next time. Furthermore, he allowed us to use their swimming pool, hot tub & on-site botanical garden (which has bazillions of orchids) for *free* after our Black Hole Drop experience. How sweet!
The Black Hole Drop experience was INTENSE & very difficult as it is uphill for about 2 hours, in slick conditions. The walk back was much easier & quicker comparatively. It's so worth it though (there was a somewhat older couple with us who were never rushed). The guides allowed us to stop at our leisure, identified local flora & fauna (saw a redrump tarantula & jaguar paw prints). All in all it was wonderful... AND THATS BEFORE THE ACTUAL RAPPELLING!
Almost everyone in the group had never rappelled before, but the guides gave great instruction & an overview of the equipment so I felt very safe. Lunch consisted of make-your-own burritos but everything was tasty! Can't thank Ian Anderson's enough for their professionalism & hospitality!