Removing 1980 450 evaporator coil

[biggame]

I've pretty much got the old gal stripped down inside and am looking at the Climate Control Unit under the dash. I can see the three nuts (front and each side) that need to be removed. I also see the two copper pipes that have connections through the firewall on the driver side next to and above the gas pedal.

Two questions:

1. What do I need to do to disconnect these pipes?
2. Are there any other secrets to removing this unit that I need to be aware of?