You may want to consider contacting the manufacturers of your appliances to see what they recommend you do. It may be difficult to give 'safe' and 'specific' advice on this Forum. The municipality in which the house is located is another source of information. At worst, talk to (or hire) a plumber who has done winterizations in your area. (In a sense, interview them.) This would probably be money well-spent as you can watch what he does and perhaps, next year, take a crack at winterization when you know more and are more confident.