We were able to get the air inside the cab down to about 48° tonight!
And then after removing the servicing hoses my dad (also my A/C guy) put the cap on the filler port as required. Meanwhile I cleaned up a little to get ready to take it for a ride. As I knelt in front of the truck I heard a hissing sound. After some investigation I found the cap on the filler port has a plunger in it that was depressing the high side shrader valve releasing the freon. I guess it was like that for a few minutes.
I took it for a ride and the air only got to 60°, so tomorrow I will recharge the system. It has me pretty frustrated as I went out of my way to buy a scale to measure how much we put in (1.8 lbs) and now I have no idea how much is in there. Whatever, I'll throw some more in to get the pressures right and then let it eat. I'll tell you this... when serviced correctly it will freeze you out! Gonna be nice for the rest of the summer!