Michael and I have stayed at Summer Place Inn as well as Villa Escondida, both in town and close to the waterfront/Melgar (main street). Both are wonderful places to stay. Very clean and safe. The advantage to Summer Place Inn is that there is a well equipped outdoor palapa kitchen and you can cook your own meals should you desire. Breakfast foods are provided, however, the guest prepares the meal. However, you can prepare your breakfast any time of day. Michael and I would often make up our eggs/toast/juice for dinner. Villa Escondida's hostess/owner Magda, prepares the full course breakfast, and a wonderful breakfast it is. Both places have fridges that you can store cold lunch items bought at the grocery store. One grocery store, Chedraui is close walking distance to Summer Place Inn located at Avenida 10 and Calle 17/19. Mega, the super Walmart like store, is just a bit further. From Villa Escondida, which is at Avenida 10/Calle 3, one could easily walk to the grocery stores, however, most likely take a cab back with your items.
However, be aware, that for diving you will need to get to a pier or to the Marina to meet with your dive op. Villa Escondida is a short walk to the town pier and Summer Place Inn is...walkable. When Michael and I stayed there we would start our walk about 30-45 min early to our pick up time. If we came across a cab going by within the first few blocks we would get it. About $3.00 USD. If we got further than that we would just finish the walk at a very leisurely pace.
I would recommend that you get two "favorite" lists together. One for Dive Op's, unless you already have a favorite and the second for your lodging. Then contact your first choices with your questions and go from there. One question for sure is if the dive op you choose picks up a particular pier or hotel. It will all work out well for sure and you will have a fantastic dive trip !
Sue