Ke, we did not get to any of the caves so I can't speak to that. Again, that will be our next trip in May. (can't wait) In one day, we went to Xuantunich, hit Trek Tours for Tubing on the River from right above Xuantunich to Clarissa Falls and still had time to visit Cahal Pech. I'm sure you've been to Zoo. We had rented a car and stayed at Aquada so there was no waiting for buses, tour guides, etc. It was a fun day. Probably would not have time to get all this in and get back to BC to catch a water taxi if you are using the buses. I know there is kayaking and canoeing around SI also. There's probably plenty of time to do it in an afternoon and a morning though. How are you planning on getting around? And, we are in our 50's and were delighted that we kept up with and did better on the ATM tour than a couple that was with us that was in their 20's! We're not hanging it up yet.