She might have a lot of adventures. For example, she could encounter powerful Uchiha ninjas and learn their unique jutsu. Maybe she'll get involved in some sort of mystery within the kingdom, like a secret about the Uchiha's power source. Also, she could form unexpected friendships or rivalries with the Uchiha clansmen.
Sakura's journey to the Uchiha Kingdom in the fanfiction could be filled with various perils and wonders. She could stumble upon ancient Uchiha ruins and find clues to a past event that has been hidden for ages. There might be internal conflicts within the kingdom that she gets caught up in. She may also use her medical ninja skills to help the Uchiha, which in turn earns her their respect and trust, leading to new alliances and opportunities for her.
Some Uchiha might be suspicious of her at first. After all, she's an outsider. But others may be curious about her skills, especially if they know she's a strong ninja from her own village. They could either welcome her with open arms if they see potential benefits from her visit, or keep her at a distance if they fear she might bring trouble.
They could encounter past Avatars and learn unique bending techniques from them. Maybe they'll find ancient Air Nomad artifacts that hold special powers.
She might encounter strange creatures. In the opposite world, there could be magical beings that are completely different from what she has known in her own world. For example, there could be talking animals with special powers.
Well, she would probably start by being completely bewildered. But then, she could use her modern knowledge of medicine to help the sick in Camelot. She might find herbs that are similar to modern medicinal plants and use them in new ways. Also, in terms of fashion, she could introduce new styles. Picture her trying to convince the ladies of Camelot to wear pants for more practical movement. And she would surely be in the middle of some romantic adventures, as the knights of Camelot would be intrigued by this strange and modern girl.
It could be about Sakura having a strong admiration or being a fan within the Uchiha context in the fan - made story. Maybe she is a big fan of an Uchiha character like Sasuke, and the fanfiction explores her feelings, actions related to that admiration.
They could go on a quest to find a lost Uchiha artifact. Naruto's strength and Mikoto's knowledge of the Uchiha heritage would be crucial in this adventure. Along the way, they might encounter various enemies and have to use their skills to overcome them.
She could meet her doppelganger. In the opposite world, it's possible that there is a version of herself with different characteristics or a completely different personality.
One idea for a fanfiction is that the Uchiha girl has a special connection to a mythical creature in the Naruto universe. Naruto, intrigued by this, joins her on a journey to understand more about this connection. Along the way, they face many obstacles like other ninja clans who are jealous of their discovery. Through teamwork, they overcome these challenges and their relationship grows stronger.
One common theme could be Sakura trying to fit into the Uchiha clan's culture. Another might be her developing relationships with Uchiha characters in a new way, like a deeper friendship or a romantic relationship with an Uchiha.
I'm not sure specifically what that particular 'sakura oldest uchiha fanfiction' is about as there could be many out there. It might be a fan - created story that involves Sakura from the Naruto series and an Uchiha character, perhaps exploring their relationship, or it could be about Sakura's connection to the history of the Uchiha clan in a fictional scenario.