Miraflores is a rather upscale district of Lima. Cosmoplitan, chic and safe to walk. It's south of downtown Lima and safe to walk. I went for a walk using the straightest path to the coast which led me to the Larcomar mall which I couldn’t resist checking out. It’ right along the cliffs where a long pedestrian and bike path runs up/down the coast. The cliffs run high and for miles.
Playa Del Carmen is a highly touristic place. However it is quite lively with many restaurants, shopping, bars, nightlife and enterainment. On the adventurous side you have many scuba diving sites on the reefs/cenotes, parasailing, skydiving, adventure parks and much more. To get to Playa Del Carmen you need to fly into Cancun then find a shuttle over.