While I still do the "pink stuff", a friend of mine has always winterized with air and never had any problems. What I do is use air first, then run a much smaller amount of antifreeze through the lines.
If you use air, here are the ideas and cautions I have heard:
1. Buy an adapter (my plastic one was $2.49) and use it on the city water inlet.
2. Keep the pressure at about 50 lb or lower, and be sure to open something first so you don't pressurize the whole system... resulting in a messy spray when you open a faucet, etc.
3. I take out the water heater anode and turn on the compressor as the heater is draining to speed the emptying of the heater.
4. Afer bypassing the water heater, I open one of the low point drains and turn on the water pump till it is blowing a bit of air(of course drain the fresh water tank first), then I apply pressure till it only emits air, then I open the other low point drain and close the first... till that one only emits air.
5. Finally I close those drains again (compressor off) and go inside to open a faucet (furthest one first in my case) then the toilet, then each of the others till it is just air.
6. If your unit is prepped for washer/dryer, don't forget those lines.
7. After all of this, I leave all the faucets and drains open for a few days (weather permitting), then come back with antoher shot of air.
8. This is the point where I also use the antifreeze, using much less than I otherwise would if I hadn't blown out the lines. (my friend omits this step and never has had a problem in the 30 years he has had RV's.)
9. Even if you don't use the antifreeze in the lines, I would strongly urge that you pour a bit of it into each of the traps so ice doesn't cause a problem there.
ALL OF THE ABOVE BEING SAID... ...THIS IS MY WAY AND MY FRIEND'S WAY OF DOING THIS, AND IS NOT INTENDED TO IN ANY WAY LEAVE ME OPEN TO LIABILITY IN THE EVENT IT DOESN'T WORK FOR YOU! 