I would recommend getting out of Cancun as soon as possible. About an hour south is Playa Del Carmen and another 45 minutes below that is Tulum. Playa used to be small, sleepy and quaint but now is constantly expanding. People from all over the world visit there. Tulum is breathtaking with it's ruins perched on a cliff above the Caribean. Also between Playa and Cancun is the Isla Mujeres(island of the women) and is only accessable by a 40-minute ferry ride. In five previous trips I've never rented a car. The inter-city buses are plush and very affordable, much like flying elsewhere. Cabs are reasonable as well. A 45 minute cab ride from Tulum to Playa was less than $20US (in 2000). I have heard several stories of rental cars being repeatedly stopped and searched by the Mexican military which usually is comprised of kids not much older than 18 carrying automatic weapons. I definitely recommend spending a few days in Merida. You can take day trips to the port city of Progresso and visit Celestrun which is famous for it's Pink Flamingoes. On Saturdays in the town square in Merida there is a market with all sorts of wares for sale. You can book a tour to Chitzen Itsa through many different travel agencies. I recommend Yucatan Trails. It's owned by a French Canadian, Denis Lafoy, who has been down there since 1979. He is quite a character. Across the street from his office is the Hotol Colon which has a beautiful tropical pool hidden from the street and decent rooms. A few years ago a single was 250 pesos but now it's more like 500. Luz in Yucatan has apartments with kitchens starting at around 350 pesos. The oldest cathedral in the Western hemisphere is opposite the town square. At the beginning of the 20th century Merida had more millionaires per capita than anywhere else in the world. I have returned to Merida several times. You will like Merida.