Yellow is the output to the wheel cylinder as you will see it is just one outlet and continually tee's off to the wheels. You will see the two vacuum tubes up on the firewall and feeding down to the HydroVac all color coded. The one thing I don't know is about the connection that is plugged on the vacuum tube marked red. Someone else might know about this and hopefully pipe up !
The other end of those (Red & Green) tubes (Drivers side) on the firewall lead down to supply the Vacuum actuated 2 speed rear. so that tubing which can be ignored and capped if you dont have a vacuum actuated 2 speed rear.
I also have not yet rebuilt or used the brakes on this truck, that is next on my list. Hopefully we can get this figured out.
