We just arrived back from the Valor, and stopped in Belize. We booked a private excursion, and were with a group of 10, compared to the Carnival excursions of 50-75 people. We did the Extreme cave tubing, and with this private excursion, we did one more cave than the group who booked theirs thru Carnival. We saw the big groups from Carnival entering the water to begin their Cave Tubing, after we had just gone through one cave allready. So, you are getting a much better, private tour for less than booking it thru Carnival. Plus, our tour guide was amazing....as we trucked our way thru the jungle on our way to start our cave tubing, he made our hike more enjoyable by educating us on what we were seeing along the way. He made the extra effort to make sure we were enjoying ourselves.
We used Islandmarketing.com
We book thru them alot, they are very reputable.
Let me know if I can get you any more info.