We went 2 weeks in Tulum in November 2011 (just after a hurricane and just before a strike...).

Because of the kids (2 and 5 years old) we prefered choosing an all-inclusive resort for 2 weeks, renting a car for to visit the places of interest for tourists.

We were in the Gran Bahia Principe Tulum (very nice : clean and recent rooms, fullboard quite nice). We toured around Tulum toward Coba, Chichen Itza and even Uxmal (with a night in Uxmal). The trips in Yucatan are easy: the roads are nice and the directions are well indicated.

Some feedbacks :
- Rent a car using internet is cheaper than renting from the agency
- On the roads, there are a lot of police check points. But the tourists seem to be spared (the trip dealers would tell the opposite): we were never controlled
- Uxmal is a little bit far from the Maya Riviera (4-5 hours). Nevertheless, the spot worths the trip because of the ruins and for the calm after the Chichen Itza crowd: if you get there early, you can be alone on the spot.