Blowing out water lines in Class A

A 12V car tire compressor will likely not be very effective because it moves a minuscule volume of air. (I'm assuming you don't mean something like a nice Vair compressor, but the typical gizmo that plugs into the cigarette lighter.) To blow the water out of the piping for winterization, you need a moderately large amount of air at a relatively modest pressure.

You might be able to get by if you used an air accumulator tank in spurts, but it would be a painfully slow and noisy process filling it back up with the inflator, and many inflators aren't really designed for continuous rather than intermittent operation.