It's possible that he secluded himself to protect his loved ones. In the Naruto universe, there are always threats. By isolating himself, he could avoid putting others in danger while he became stronger. He may have also been secretly gathering information about his enemies during this time.
In a Naruto 3 years seclusion fanfic, Naruto could focus on intense training. He might master new jutsus that he didn't have time for before. For example, he could develop a more powerful Rasengan variation. He could also gain better control over his chakra, perhaps even unlocking new levels of his Nine - Tails chakra. This seclusion time would be like a cocoon phase, where he emerges as a much stronger shinobi.
The Nine - Tails could be considered as a 'visitor' in a way. Since Naruto is in seclusion, he has more time to interact with the Nine - Tails inside him. Also, it's possible that some of the spirits of the past Hokages might visit Naruto. They have a connection to Naruto, and they might want to guide him during this important time of self - improvement. They could share their experiences and knowledge to help Naruto become a better shinobi.
They could visit the Hidden Leaf Village's annual festival. There would be games, food stalls, and performances. Naruto would be eager to try all the games and win prizes for Hinata. Hinata would be shy but would enjoy seeing Naruto so excited. They might share some cotton candy and watch the acrobats perform. It would be a lively and fun - filled date that showcases the village's culture.
Well, they might have a deep conversation. Naruto could open up about his dreams for the future of Konoha and Sakura could share her medical ninja goals. They might also get into a friendly sparring session as a form of entertainment during the date.
They could go to a training ground. Naruto would show off his cool moves, and Hinata would cheer him on. Maybe Naruto would teach Hinata a new technique. They'd laugh and have a great time together, getting closer through their shared love of ninja skills.
During their wedding night, they could have a friendly spar. Not a serious fight, but just a bit of fun play - fighting like they used to do when they were younger. It would be a way for them to connect on a more physical level while also showing how much they trust each other. Then they would end the night by falling asleep in each other's arms, feeling content and loved.
In the 'naruto meets his brother fanfic', it's possible that the brother has a different view of the ninja world compared to Naruto. This could lead to some interesting debates between them. The brother might be more cynical or have a darker past that Naruto has to come to terms with. There could also be a rivalry at first, but as they get to know each other better, they form a strong bond. Maybe the brother has some special abilities that Naruto has never seen before, and Naruto is eager to master those abilities as well.
In such a fanfic, Naruto might initially be confused when he meets his counterpart. They could compare their lives, skills, and experiences. Maybe they would have a friendly spar to test each other's strength.
It could be that Naruto returns to a world that has changed a great deal in his absence. There could be new political situations in the ninja world. For example, new alliances might have been formed between different villages. Naruto, being Naruto, would probably try to bridge any gaps or misunderstandings. He might also discover new talents among the younger generation of ninjas. He could take on the role of a mentor, just like some of the people who guided him in the past. His return could also spark a new era of peace and cooperation in the ninja world as everyone looks up to him as a symbol of hope and strength.
In such a fanfic, Naruto might finally get to understand his family heritage better. His dad could teach him some new jutsu that only the Uzumaki family knows.