I practiced some sections of the run, and will try a full run offline shortly.

Is saving, quiting, and reloading the file allowed? The rules say that it depends on the game (If I'm right). I thought of routing the game and see if some backtracking to recruit a player can save time etc. Recruiting certain players in the game is dependent on random luck (the menu appears showing 5 players form the team and sometimes the specific player won't appear; saving before you see the menu then quiting + reloading the file will "reshuffle" the players list before you talk to the manager)

I don't know, this route idea might be embarrassingly stupid at the end, but I still want to give it a try.

There's really no issue, the only requirement is that it's RTA, so... IMO it won't really pay off: the default team is more than enough to beat the game.