I've learned to pack something to scrub pots and pans with also - SOS pads or some sort of sponge with a rougher side for scrubbing. Our last time staying at WH, we didn't get around to doing any "real" cooking until later in the trip. We pulled out the pots and pans we needed only to discover that whoever used them last did not clean them thoroughly. They had been put away with dried food still stuck to them and apparently the cleaning crew either didn't catch it or didn't bother to take care of it.

We didn't have anything on hand to deal with it - the dish cloth and little sponge that were provided were NOT going to cut that. And we didn't have time to soak it off and then cook or make a run to the store to get more cleaning supplies. I think we ended up stopping off for something on the way to the parks or waiting to eat after we got there. And some of the food we'd bought went to waste. Not the end of the world but I was not pleased.
There are several other things we usually take. But we drive down so this may be a bit much for folks who fly. Some of those other items are a small bottle of Shout stain remover or a stain remover stick (in addition to the other laundry supplies already mentioned), clothes pins, bottles of liquid soap and solid air fresheners for the bathrooms, and cooking items like salt & pepper, any seasonings I plan to use, cinnamon sugar for the kids' toast, etc. I tend to pack a lot to take down not only to save money but to save shopping time once we get there. I hate using up precious vacay time to shop for groceries. Plus it always takes longer to find everything in an unfamiliar store.