There are a lot of cab discussions if you search here. I want one, but the prices are really kind of ridiculous for what you get.
Looked at one from craigslist down by Geneva a couple of weeks ago. It was for a different tractor, looks like a big older garden tractor. Didn't look like it would work w/ the curved fenders on the 2305, but if you're into hacking you might be able to make it work.
Otherwise I'm waiting for a nice recession fire sale somewhere...
Check out "Original Tractor Cab" on google... I bought one for my 2320 for $650 and it worked beautifully during the winter months. Very complete and of great quality - just have to be more careful than a hard cab, as it's all fabric (except for the fiberglass roof panel) with metal support rods.
I've had a Original Tractor cab for a 425 sold that tractor and cab . Bought the 2210 and then a cab and traded that tractor for the 2305 and still using the cab
This summer I have left the frame ,roof, and windshield on tractor .
I have that cab on a 4110 and yes in really cold weather they do fog up. But, I bought a $15 fan and it takes care of that problem nicely. Just like the defrost on a car.