The Conch train tour was great. The driver was very informative and well versed in the city history of Key West. The tour lasted about 1 1/2 hrs and you had the option to hop off on two different stops and hop back on on the next train.
We took the Ancient Culture/Mayan Ruins & Island Sightseeing. It was on an air conditioned bus. The tour guides Alex and Silvia were excellent and well versed in the history of the Maya Ruins and Conzumel. I do recommend to take or buy mosquito repellent. There is a lot of mosquitos around the ruins and there is nothing they can do about it., But with mosquito repellent you should be ok.