You don't need much for this trip, just one suitcase should be enough. Somewhere to pack a pair of jeans, a few shirts, and maybe a swimsuit. I hear the weather will be nice out. Maybe we could immerse ourselves in the ocean, let the salt stick onto our bodies, then when we wash it away it will take the old age in our souls along with it. It would be nice to feel so young that we bubble over with laughter again.
You might also need a blanket, but just the small, fluffy kind. Something soft and that smells like sweets, tranquility, and home. Something to wrap yourself up in when the fun gets too chaotic for you. I'd recommend you bring a nice dress along with you too. One that looks like it came straight out of a children's fairytale book. One that reminds you every so often that you are a princess, even if no one ever sees you in it.
You won't need much more than this. Leave room to pack lots of other things that you come across along the way. Things like pictures of all the amazing places you pass through. You might decide to buy a souvenir, or two, and need to fit those in too. You might redefine happiness and need a place for it, or find an infinite amount of joy in the foreign night sky- foreign, yet still just like home.
You might find love. Love in the blue of the sea, or in the purity of the air. You might even find love in the person you will become. Leave space for all these things, they are important.