There may be other options - but I have an adapter (just check amazon for rv air blowout adapters - there are lots of options). Mine is like this - https://www.amazon.com/Winterize-Mot...ef=sr_1_2_sspa
Hook it up where the city water hose is connected. Make sure your compressor is set lower than 55 PSI (so you don't blow your lines). While compressor is running, go to each faucet and open it until air blows through. Do both the hot and cold lines. Don't forget the toilet and outside shower if you have one.
And that should do everything - including the hot water tank. I always make sure there's antifreeze in the drains so any water in the trap won't freeze. And I also open all the taps (not the toilet) after I turn the compressor off. That way, any water that may have been missed will have room to expand.