I just learned something about Ethylene Glycol verses Propylene Glycol that is used in the RV antifreeze. Check the ingredients for the Propylene Glycol not Ethylene because the alchohol type will dry out rubber seals and some types of plastic plumbing while the propylene type lubricates rubber seals and does not damage plumbing pipes. It costs a little more but well worth it.

I've been reading about this as well.  There is a company that makes (very expensive) waterless coolant largely from Propylene Glycol.  It isn't poisonous, it doesn't boil until 400F or so... great looking stuff.  evanscooling.com  

Very pricey, but should last the life of the vehicle.  If I ever buy a new truck... or rebuild this one, I will likely put that stuff in if I can afford it.  

RV antifreeze is not made for an engine. it for the pluming in an RV. sink traps and water lines. we use it in out pressure washers as well.

however the link CSM posted is great stuff.

As for what CSM posted is more of a engine coolant than a RV water system antifreeze.

Typically I just use compressed air and blow all the lines out dry. This year being a bit of hurry to beat a freezing night I quickly blew the lines out and loaded with RV antifreeze. Problem with RV antifreeze if there is still water in the lines it will still freeze solid might not expand or as much as water alone would. Typically I spend a better part of a day cleaning out, blowing out and shutting down the RV for the winter.

Personally even RV antifreeze I'm not fond of because of the smell and possible after taste you might get.

Mine usually never sits unoccupied. One winter about 5 years ago it did and I filled it up with rv antifreeze. Even today when ever I turn the hot water on, the smell is still there. It goes away in about  20 seconds or so, but it is still there. I wont use it in the water lines again unless it is an emergency.

I popped a copper water line in my prime 1972 Avion travel trailer a couple years ago due to the use of RV antifreeze, had it throughout the system and purged with it but it does freeze still in sub zero temps, have other friends who had the same issue using it, we have all since gone to blowing out the water systems with air now just pour just a bit of RV down the drain traps to help if there is a small bit of water left there.

I've never seen the appeal to use RV antifreeze.  It take 10 minutes to blow out the lines with my air compressor and I've never had any issues.  I do add a bit of anti freeze down the drains, but that is it.