There's a chance they might develop a romantic relationship. As they spend time together at Camp Rock, they might start to have feelings for each other. The way Nate looks at Caitlyn when she's singing, or how Caitlyn blushes when Nate gives her a compliment could be signs of a budding romance.
Another possibility is that they become rivals. Maybe they both want the same solo in the camp concert. This rivalry could be friendly at first, but as the competition heats up, it could put a strain on their relationship, whether it was a potential friendship or something more.
There are a lot of possibilities. They could be from different groups at Camp Rock. When they meet, it causes a stir among their respective friends. But as they start talking more, they find out they have more in common than they thought. For example, they both have dreams of making it big in the music industry outside of Camp Rock. Their meeting could be the start of a journey where they support each other to achieve those dreams.
Character interaction is also a big theme. The different personalities from both shows collide. You might see David from Camp Camp trying to keep everyone positive in the face of Gravity Falls' oddities, while Dipper is trying to figure out how to use Camp Camp resources to help in his mystery - solving. It's really interesting to see how they play off each other.
Another option is to check out some fanfiction communities on Reddit. There are subreddits dedicated to both Camp Camp and Gravity Falls where fans might share or discuss their 'camp camp meets gravityfalls' fanfiction ideas or links to their works.
A potential storyline could be that Gine saves Goku from a powerful enemy. Since she is his mother, she has a strong instinct to protect him. Another could be that Goku and Gine team up to fight against Frieza or other villains who pose a threat to the universe.
In a 'Naruto meets Konan' fanfiction, there could be a time - travel plot. Naruto somehow gets sent back in time and meets a younger Konan. He tries to prevent some of the tragedies that happened in her life, like the death of Yahiko. This changes the future and creates a whole new dynamic between Konoha and Amegakure.
Well, 'rock meets zero fanfiction' might be a unique piece of fan - created work. Maybe 'rock' represents something solid, strong or a particular rock - like being, and 'zero' could be a symbol of nothingness or a starting point. The fanfiction could explore their encounter, how they interact, and what kind of story unfolds from their meeting, perhaps in a fictional universe that combines different elements.
One interesting story could be about a new camper at Camp Rock who has a unique musical talent that no one has ever seen before. This camper might face some challenges at first, like being shy to show their talent, but eventually overcomes it and becomes a star at the camp.
Shane Gray is also a favorite. Fanfiction might focus on his life before Camp Rock or create new scenarios where he has to make tough decisions about his music career while at the camp. For example, he might be offered a big record deal but it means leaving the camp and his friends behind.
Obviously, Nate 10 would be one of the main characters. And from My Little Pony, Twilight Sparkle is very likely to be a main character as she is often at the center of many adventures in the pony world.
One possible interesting story could be Nate 10 using his powers to help the ponies in Equestria solve a big mystery. Maybe he teams up with Twilight Sparkle to figure out why some magical artifacts are disappearing.