We LOVED Tulum. LOVED it. We're going on a family cruise in July, so we're postponing a second trip until then.
It was a 45 minute high speed catamaran ride (be prepared for motion sickness), a short walk, and then an hour or so on the bus. Once off the bus, the bathrooms are in a jewelry store where, you know, aggressive but polite salespeople. Then another 10 minute walk or a couple dollar (cash only!) tram ride to the actual ruins. Our tour, with RCI, provided us with personal headsets so that we didn't have to crowd around our tour guide as he talked to us about what we were looking at. We then had some time to wander around on our own, before meeting back at the bus. It was gorgeous.
The driver and the tour guide expected tips, just an FYI.