The lighter you can travel, the better. We were on formula at 7 months when we went. I took enough nipples for one day and used disposable bottles. Then I would do "dishes" at night--so a little thing of dish soap (I used an old travel shampoo bottle). And to the parks, I only carry what I need for that time out. We would go back in the afternoon so I would repack for each time out--usually one meal and a diaper.
We also had toys for when we were getting ready. But you never need as many as you take because you're never in the room long enough to lounge (us anyway). When kid was awake, we were off and running.
And while it's expensive, your resort will have anything you need. My 40-pack of wipes was gone one day before we went home. So I bought some at the gift shop. They're not going to go to waste, they're just more than you'd pay at Target.
Give us your list when you get back and we'll fill in the holes for you.