I don't think there is going to be any right or wrong way to get the cables to the doors. You know where its starting from and where you need to finish, just look and find the easiest path.
You should be able to get speaker cable into the driver's door by following where you took the RCA cable instead of going down the side of the truck, get it behind the parking brake bracket.
Yes your going to have to remove the B-Pillars again, unless you want to half ass it and don't run it properly.
Just stick your head in the floor board and look behind the glove box. If you pull the headunit out, it may make it easier because light will be shining through and it will make it easier to see open spaces behind the dash and glove box.