It's a lot of fun but bringing a few essentials made our trip way easier.
Our 11 month old is still drinking formula so we had to purchase drinking bottles, dish soap and a wash basin. I brought my own bottle drying rack and bottle cleaner.
The whole cleaning bottles with bottled water - SUCKS, but has to be done when visiting Mexico. Just tip your room attendant and let her know that you require extra bottled water.
Next, a full UV protected body suit and hat and baby sunscreen. Highly recommend trying the sunscreen at home prior to your trip to ensure your infant is not allergic.
Stocking up on baby pouches, crackers and snacks that baby likes is important. Sometimes you are stuck on a bus or plane and snacks are required!
Finally, bringing an umbrella stroller is essential and can be picked up at Toys R US for a decent price and checked at the airport gate for free will make your trip run smooth.
Good Luck!