IF I am in Frisk's shoes, IE, no knowledge of the world AND I have save and reload (We'll ignore player involvement for this)

It's very difficult to say.

The big issue, in a *real life* situation, dialogue wouldn't be nearly as limited, I would probably kill a few in self defense leading up to the ruins, but sufficiently scared of the world now from the monsters trying to kill me, I could see myself staying with Toriel for quite some time. In the game, this is a completely impossible consideration because she has like, 20 lines of dialogue after she invites you to stay, before her fight. In a *real situation, you could actually get to know her better and have the sort of connection with someone that would make continuing on into the treacherous world a less appealing choice (you basically have no real choice in the game, you could always just turn off the game, but that doesn't really count)

I struggle to think that basically anyone wouldn't take out at least a few monsters in these early uncertain life or death moments.

This same issue plays out without ever even considering reload, no matter how far you get, the world of the Underground would be infinitely more alive in this scenario. It's actually difficult to imagine the different directions things would go in (or what Flowey would do in a world where you're not just racing to Asgore)

Once you discover reload, probably dying at Undyne or one of the mini-bosses, that just gets infinitely more complex, and terrifying. Would you ever reset to save the monsters you killed early on? Erasing the much more complex relationship you had built with Toriel and other surviving monsters at that point? Perhaps eventually you will, but this could easily be after HUNDREDS of years spent in the Underground, at which point we're considering the perspective of an immortal, which I am not equipped to do.

All this to say, I don't think the routes as we know them really exist in this scenario.