get yourself a nice clean double blanket.Remove the 3 bolts on the a/c compressor and move it aside on the right fender..this way there is no damage done.
On the left side remove the pipe to the heat exchangers..2 bolts on the heater motor and one hose clamp.this will give plenty access to do the valve adjustment on top..
there are also many way to do the valve adjustment..mine is like this..mind you i do it for almost 40 years...but if you practice with the feeler gauge you get there....
Ivan
https://www.youtube.com/watch?v=O_ypBn_u7g8