We took a child like this on a big day out for DS's birthday.
We'd been in the car for an hour when he decided he'd rather go back to our house to play on the Xbox than to the zoo.
When we didn't immediately turn the car around he made a noise, which he said he was going to keep making until we got there.
We arrived at the zoo.
He didn't want to look at any of the animals, except for one enclosure as far away as it was possible to get from the entrance. And when we got to that enclosure, he didn't like it and wanted to go back out.
He didn't want to play in any of the playground bits that were dotted about. They were either too big, or for babies apparently.
He didn't like the bench we sat on for lunch.
He didn't like the food we had for lunch.
He didn't like the ride around the park on the monorail.
He didn't want to do anything, because it was all boring. The animals were boring, the playgrounds were boring, everything was boring. He thought we should go to the gift shop and then go home, and he was saying this before we'd even paid to get in.
At the end of the day we went to the gift shop. He'd been agitating for the gift shop all day. I told them both they could choose something for about £10 each. DS chose something. DS's friend walked around the shop five times declaring everything to be boring. "I don't like that. I don't like that. That's for babies. That's boring. Books are boring. I don't like those."
Turned out he thought the gift shop might sell Disney Infinity figures, which he could bring back and use on the Xbox.
We arrived home and dropped him off at his house and his Dad asked him if he'd had a good time. No, it was boring. Yeah, says Dad, do you want to go on the Xbox?
You have my sympathies OP. We had this for a day, you have this for the length of a holiday.
You might have to have a word with her and tell her that if she stops complaining she might actually enjoy herself. Children who don't know how to enjoy new or different things to what they are used to are hard work.