I rewired my whole house and only had to cut about 3 holes into the walls, so let me share my tips:

First - get somebody to push wire in on one side so you can pull on the other.

When you pull with string, I trim the wires to leave a nice taper, and tape it all so it doesn't snag.

Get a borescope, you can drill a 1/4" hole in the wall cavity and see what's happening in there. That patch takes like 30 seconds.

I pull the electrical box out before cutting holes, as that's where you need to see.

Don't use a sawzall anywhere - holesaw and hand stab saw with drywall fleam teeth are your best tools. I use the hand saw to gently open around boxes so I can see where wire goes, and then remove box if needed.