Winterizing

A compressor will get rid of most of your water, but to do it right I would also use RV antifreeze. Don't forget to open your low drains and empty your water tank. If it gets really cold where you are use the antifreeze.

You need a compressor that you can regulate down to 35 psi.

You can use pretty much any air compressor but I'd use a pancake compressor with a 6 gal tank at the minimum. You are just pressurizing the lines of the camper so it doesn't take much volume to fill them. A compressor like a 12V car compressor will probably run too long enough to risk burning up the motor if you tried to use one of those.