They could also travel to a time during one of the great ninja wars. They might get involved in battles they previously only read about in history books. Sasuke could team up with his ancestors and Sakura could learn new medical techniques from the medics of that time. This would not only change the course of the war they are in but also bring back new knowledge to their own time.
One idea could be that Sasuke and Sakura travel back to their childhood days. They could then use their knowledge of the future to prevent certain tragedies from happening in the village. For example, they might stop the Uchiha massacre, which would change the entire course of Sasuke's life and their relationship.
Another plot could be that they travel to a time when the Akatsuki was first formed. Naruto might try to persuade the members to choose a different path. Sasuke could explore the reasons behind the Akatsuki's creation more deeply. Sakura could use her skills to heal some of the wounds that led to the formation of the Akatsuki in the first place.
One idea could be that Sasuke and Sakura travel back to the time when the Uchiha clan was still alive. They could try to prevent the massacre. Sasuke might have the chance to talk to his parents and change the fate of his family. Sakura could use her medical skills to help those who were injured during that chaotic time.
One idea could be Sasuke traveling back to the Uchiha massacre. He might try to prevent it, which would completely change the Naruto storyline. This could lead to him having to face off against Itachi in a different context, not as an avenger but as a protector of his family.
One idea could be that Sasuke and Hinata travel back to the time when the Uchiha clan was still intact. Sasuke gets to see his family again and Hinata witnesses the power and unity of the Uchiha. They might try to prevent the tragedy that befell the Uchiha clan. Another plot could be them traveling to a future version of their world that has been completely destroyed. They then have to figure out how to go back in time to change the events that led to this destruction.
One idea could be Sakura traveling back in time to her genin days with the knowledge she has now. She could use this to train harder and avoid some of the mistakes she made before. For example, she might focus more on her taijutsu skills from the start.
One idea could be Sakura traveling back to the time of the founding of the Hidden Leaf Village. She could use her modern medical knowledge to help during that era, and perhaps even change the way ninja training incorporated medical skills. Another plot could be her traveling to a time when a great war was about to start, and she uses her skills to prevent it by bringing the different sides together through her diplomatic skills and understanding of different ninja clans.
Another plot could involve them traveling to a time when their own clans were in a different state. For Sakura, she could see how the Haruno clan was more prominent in the past. Shisui could witness the Uchiha clan before all the unrest. They might get involved in family affairs and end up changing the future relationships within their clans in unexpected ways.
A great plot idea is that they time travel to the founding of Konoha. They meet the first Hokage and his comrades. Sakura, with her medical knowledge, could offer to help with any ailments or injuries at that time. Hinata, with her gentle yet strong nature, might inspire the early ninjas to be more inclusive. They could also accidentally change some small things that have big impacts on the future of Konoha, leading to a series of adventures to fix things.
One idea could be Sakura traveling back in time to prevent a great tragedy in her world. For example, she could go back to stop the destruction of her village. Another plot could be her traveling to the future to gain knowledge that would help her in the present, like advanced medical techniques to heal the wounded in her era. And she might also time - travel to different historical events in her own world's past to discover secrets about her family or her powers.