I am very thankful to have been born way north of the mason dixon line, where temps like that are seldom an issue. If I were ever to live south of Gettysburg PA, you can bet your bottom dollar I would have me a cabbed tractor. The only way I would consider living that far south in the summer would be at gunpoint though.So be directed by the fear of the "unknown"? Oh, and the windows on these can open.
Your personal preferences are one thing but tell me what you'd want if you were cutting 200 acres of hay at a 101* temp outside and you had to do the same thing the next day and the day after that and so on.
Now I'm in the woods mostly with mine. Its major jobs are plowing snow and skidding logs out. I am constantly hopping off and on when skidding plus my woods are rather dense.
A cabbed tractor would not fit in my world as well as an open station. For others it would be the opposite.
But far be it from me to establish an overall reason why a "cabbed" tractor should be avoided with the reasons you gave.
Why don't you just use horses previously suggested because your tractor might break down.