Does anyone know the easiest way to run new speaker wire through the sides of the car and into the boot/sleeve and holes in the door? I have taken off the kick plate to access the front door boots/sleeves, but it looks like I am hitting a dead end and can't get to the inside of the boot/sleeve? Any ideas?

You can feel inside the door fairly easily for where the sleeve goes out of the door. Look inside the car and you'll see a big foam grommet where the wires from the door come into the car. Partly pull out the grommet, then do your best to snake the wire down.

It's not fun, but it works.