We didnt fancy the trip to Caracol with our 3 year old so this was an obvious choice. Its an impressive structure and fun to climb, although you do need to take care with kids. We visited on a Sunday and it was quiet, but a large tour group did arive as we were leaving, so sometimes you need to be lucky.
If you have a car then you can easily cross with the ferry and drive up the hill (not recommended to walk with young kids). You can go round the whole site in about 90 mins, depending on how fit you are, and there are drinks/snacks available at the entrance.
We really enjoyed our visit and it was far superior to Altun Ha.
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