Konohamaru Sarutobi (Naruto)

The Third Hokage's grandson? All Right, my mind goes to him replacing Naruto with Naruko and maybe getting Uncle Asuma's girl Kurenai for himself. Then there's his teammate Moegi and maybe making Tsunade "apologize" for taking his grandfather's seat... of course the latter is for after the invasion and that's if Kono lets his grandfather die.

Which brings us to the when: When Naruto graduated? Maybe bump Naruto's age up and make him into Naruko and she's your personal fangirl bimbo with her mother gladly falling over herself to be his good little Uzumaki whore? Can get Kurenai as a sensei with whoever you want on your team or have Kushina and/or Mikoto Uchiha be your personal sensei(s) and Kurenai gets an all girl team for you to enjoy and then ensure she's unsatisfied with Asuma and cuck him into a good obedient boy. Hell, bring in Kono's mother since we don't know if she's alive or dead and bring in Biwako and make her still fuckable since marrying an older man isn't that strange. Can make the Biju into females that he keeps as pets

The Invasion? Not a bad time to get a bloodline or something like it to activate, can be the big hero, maybe get some enemy kunoichi as your slaves, and then ensure that Tsunade knows her place when she becomes Hokage, meaning that she's to be on her knees with her tits out any time you're near each other and she's also ready to fuck.

Shippuden? Make sure Naruto/Naruko gets a proper welcome home while ensuring Tsunade now does as she's told with missions and assignments. And then start interfering with any events you don't like while getting plenty of female options.

Boruto? Plenty of milfs to enjoy, can even cuck Naruto for taking the Hokage seat from you while banging his mother, sister, and daughter (or daughters if Boruto is turned to Boruko) all while still fucking Hanabi and Moegi, making Tsunade "pay her debts" to you, and even more.

There's also the consideration of maybe he's not in Konoha anymore: Maybe he was kidnapped when young? Or maybe he defected when they replaced Hiruzen "so soon" or maybe he defected when Naruto was made hokage instead of him? Plenty of options to choose from.

A different world all together? An oldie but goodie, and it's not like he has to go alone, and he can just edit himself to handle any new world threats.

A custom built world? Well that ensures you get what you want and have a multitude of things to choose from since not only humans have to be in the new world. Kono can literally be anyone and thing he wants and make any woman be anything and one he wants.