To be clear, Costco is not a city in Mexico. It’s really Costco. In Puerto Vallarta. It all makes sense. Of course a city with tons of retired Americans has a Costco. Talk about creature comforts! Upon discovering the Costco, we hopped in an Uber (another export), to see what was the same and different at El Costco. The underlying mission was an homage to my dad, one of Costco’s biggest fans. We had traipsed to Mexico to celebrate Dia de los Muertos, and a toast to dear old muerto Dad was in order. Costco did not disappoint. Their mango smoothies, with which we toasted, were off the hook—pretty much…