This is the Tulum tour:
Leave Cozumel by ferry to Playa del Carmen mainland: 30-45min.
Walk from pier together with guide to parking lot: 10-15 min.
Drive to rest stop: 40 min.
Rest stop for toilet and souvenir purchase: 20-30 min.
Continue drive to Tulum: 10 min.
Arrive at Tulum parking and walk to ruin entry: 15 min. (or 3 min if tram is taken).
Visit Ruins: 1h 45 min. to 2hrs.
Drive back to Playa del Carmen: 50 min
Walk to pier: 5 min.
Take tender back to ship or downtown pier: 30-45min.
Times vary from cruise line to cruise line and RCCL brings guests back to downtown pier for additional shopping. These guests must take a taxi back to the ship at their own cost.
Price for the tram at Tulum is $3.00 p/p. Also there is a cost for video cameras (not for foto cameras) of approx $8.00 - $10.00. Ruins are roped off, there is no climbing allowed. There is access to beach area and swimming possible. Make sure to bring water and sun protection as well as steady walking shoes and some cash in case the guide gives his best.
Hope this info helps, good luck.