A few thoughts after coming back from Mexico.
Safety – I found all the three places we visited to be quite safe. I still would not walk by myself anywhere at night, but as a family, it was safe to walk in the early night. I am not sure about after 9 pm as we were not out that late any day. I think in Playa del Carmen on 5th Ave, one can be out late also. Other places were all safe in the day time without any issues.
Money – If one is not staying at one of the all-inclusive places, then I would budget minimum 100 pesos per day per person. That would include only the food. Any shopping would be separate. Food is not exactly cheap, but we found that paying in pesos was cheaper than paying in dollars. And a lot of restaurants would charge more with credit card, so better take cash.
Shopping – I wish I had known that I would find everything in Cancun's Mercado 28 so I could have skipped all the shopping everywhere else, especially Playa del Carmen was the most expensive of all places. Valladolid was really good for general shopping, clothes, shoes etc. But I would not have shopped at Chichen Itza either. It seems that you would not find these things elsewhere, but we found everything in Cancun and better prices.
Food – This was a little bit issue for us because we are vegetarian. But we did not really have problems anywhere. We were happy with pizza also. But even street food could be made vegetarian. So all good. I would say some of the food was really tasty, the sauces were very good and guacamole was just great! There were chips and sauce everywhere. Street food was actually quite tasty.
Transportation – It was not that difficult to get around in this part of Mexico. The Ado buses connect cities and are comfortable. Within the city there are plenty of taxis and one can bargain but can get good price. We were able to reserve taxis online also to and from airport. All transportation was on time and safe and clean.
Time – I always feel that I need one more day in these places I visit. I would have liked to spend one more day in Playa del Carmen and gone to visit Cozumel and Tulum. Xcaret was definitely a good visit but it was a controlled environment. I would have liked to see more of nature. I would have also liked to stay one more day in Valladolid and maybe visit some cenotes – although that is debatable, because almost all cenotes charge 40 or more pesos per person to visit. So it probably would become and expensive day. But I do miss not going to even one.