This is for Let’s go Pikachu,
So I don’t have Light Up and I’m at the rock tunnel.
I’m pretty sure there is no current way for me to backtrack to route 2, so is there a way to get through it without light up?
Light Up is completely optional. It makes the journey easier, but it is by no means a necessity for you to get through the cave.
Its a little difficult but with time- (10-15 min.) - it is possible
I did it in my first yellow playthrough and you can do it by walking inside the edges of the tunnel and you'll realise how better the battles are when a trainer spots you in the dark