I love to plan and here was my quick Vacay schedule for Riviera Maya. Maybe it will help you plan!?!?
5 nights, 6 days
Day 1/Night 1:
Arrive in Cancun, Mexico.
Taxi straight to Riviera Maya (About 1 hour 20 minutes from Cancun Airport to Riviera Maya.)
Enjoy Hotel & Beach, Resort life
Day 2/Night 2:
Day in Riviera Maya
Find activities (Cenotes, snorkeling) in Riviera Maya; ride Collectivo (save on transportation costs).
Day 3/Night 3:
Day in Tulum
Find activities (Ruins, Beach) in Tulum; ride Colectivo van (About 30 minutes from Riviera Maya)
Day 4/Night 4:
Day in Playa Del Carmen
Find activities (Beach, Shopping) in Playa Del Carmen; ride Colectivo van (About 30 minutes from Riviera Maya)
Check out Playa Del Carmen nightlife
Day 5/Night 5:
Day in Cozumel (30 minutes to Playa del Carmen, then 45 minute ferry ride to Cozumel). Water Taxi fee $$
Day in Mayan Riviera (Shopping, Beach, Resort life)
Day in Akumal.
Find activities (Snorkel with Turtles, Beach, Shopping) in Akumal; ride Colectivo van (About 35 minutes from Riviera Maya)
Pack for Home
Taxi (About 1 hour 20 minutes from Riviera Maya to Cancun Airport).