I hope you find these pictures and tips helpful. This is how I ran new speaker wires in my 1999 Ram 1500 Extended cab.
The rear doors were super easy because the Molex can be totally removed to run the new wires.

The front doors were a little more work but not too hard. I used a coat hanger. Looking from inside the cab, I found a small space I the bottom right hand corner. You may find a flash light a mirror helpful in locating the space. I bent about ½” of the hanger tip over so would not tear the boot or damage the molex. You can also apply a single band of tape just below the bent. Make sure that you get it as flat as you can before inserting in beside the molex. On the door side, I pulled the boot into the door but not enough to separate it from the truck side. Once the hanger was past the molex inside the boot I lightly pulled on the boot on the door side to straighten the boot ribs so the hanger would slide better. I also bent the hanger every few inches so it follow the path of the boot. Once the leading end of the hanger was in the door, I taped the new speaker wire to the tail end of the hanger and pulled in through the boot. The cut the speaker wire to a point before taping it to the hanger. I started the tape on the hanger and wrapped in onto the new speaker wire. It took less than 5 minutes and is a complete clean install without any cutting and it is weather tight.
Hanger pulled through molex and boot

Hanger through molex inside the door

Good luck. I hope this helps.