I replaced door glass on a 4720Ch, and there is no way you would take them on and off, its tricky and defiantly 2 man job. Mine is in Houston Area and the AC has never worked well.
I clear trees with a tree saw and grapple bucket, but usually pass through with a dozer for stumps. Not using the tractor for that, but I definitely prefer the HST over clutch for that sort of stop and go work. If I was plowing fields or mowing, (steady forward speeds) I would go for the clutch.