My family and I had the pleasure of staying at Casa Mango for 4 nights in August 2013. The family consisted of my parents, my wife, and my 20 month old son. When we travel we like to explore new places, but also try to have some comforts of home, especially with a little toddler. Therefore, we needed a place that had a kitchen, couple of bedrooms, etc. and decided that renting a house would be more useful than staying in a hotel -- and came across Casa Mango.
We stayed at Casa Mango at the start of a 2 week trip in Mexico and were extremely happy from the beginning. The property itself is very new and has all of the necessary comforts of home; private baths, new appliances, even a waterfall in the pool (which our son absolutely loved). It's located in a residential area, with a security guard at the entrance of the street, so it is very safe.
As for the owners, Vivyana and Toon were extremely responsive to questions, making the reservation, directions, etc and welcomed us personally upon arrival. They made sure we had everything answered about the house, the locale, our needs, etc.
We did day trips to Chichen Itza, Ek Balam, and Rio Lagartos (each on a seperate day), which worked out perfectly. We left in the morning before it got crowded or too hot and were back by lunch time at the house and the afternoon to explore the local town or hang out in the pool.
If you are looking to stay in Valladolid, we highly recommend Casa Mango. The location makes it ideal for day trips to all of the major sites as the title indicates. As for supplies, there is a supermarket (with everything you need, even TV's) around the corner and the main square only 3/4 mile down the road.
All the best