A combination of 3 - 4 days in Playa del Carmen and 2 - 3 days in Akumal or Tulum for a slower pace are great for anyone interested to try something different.
Day trips are always a great options, especially since you are never too far away from home base. Tulum is only 25 minute south of Akumal... only 25 minutes south of Playa del Carmen.