Fixing the leaks is likely to mean taking it out of service for years. While it is a good idea, it means the truck is off the road while I do a huge amount of body work. It rarely gets below freezing around here, and most likely those days I'll drive something else.
I don't want a panel truck and would have trouble pretending my Suburban is one...
I like the rear heater idea. Currently is has no seats behind the front pair, but I see no reason now to drop a second heater back there.
I did drive it to and from work today. I had to dry the windshield with a rag a couple times, but before I'd gone a mile it was staying clear enough to be comfortable.