I use something like this:
Tractor Supply Compressor
You want something that can supply you with air long enough to get most of the moisture out of the lines, so it does not trickle down to a low spot in the piping and cause damage if it freezes.
I am going to replace a run of copper in mine shortly. I "repaired" it with a short length of heater hose, but it keeps coming apart, because it is to far under the bathtub to reach and get a good grip on the pipe to attach the hose. I am going to replace the whole run with copper.
A locking air chuck is also very helpful. Let's you lock the chuck on the schraeder valve so you don't have to sit there and do it yourself.