2 questions!

Go to MyMopar and download a factory service manual. I don't remember if it's Dodge or Plymouth. Vacuum diagram/ troubleshooting on AC / heater is towards the back

I don't remember anymore I believe there are only two vacuum hoses through the firewall. One goes to the heater/ coolant valve, the other ties in with the vacuum system, and there is the little round reservoir tank as well "in that mix"