My pleasure goldeneagle!
Welcome to the next phase of your mv addiction!
I know when I started my build, there was more time spent laboring over what and where everything was going to go and how it was going to work, than time spent actually working on it.
There is a lot of design on the fly prosses that goes into a man cave camper!
Concerning the air conditioner, if I might suggest, a window shaker with heat usally starts around 12k btu, that requires a much larger hole to mount and may be way overkill for the qubic feet.
Since your using propane, a small rv furnace would work nice for heat,and you could use a smaller ac unit, say 6k to 8k btu.