Touring means your arse is in the saddle for a very long time and roads can throw up surprises so think comfort at all times. What might be a good commuter bike for those short trips may not be ideal when you are in the saddle many hours. You don't want to be constantly reminded your arse is hurting when you are trying to enjoy the scenery as you cycle. Think about where your touring and also what reliability issues the bike might throw up, i.e. low end drivetrain, thin 700c wheels, brakes and suspension etc. Keep it strong and simple with comfort as the no.1 priority.
Here is a touring bike meant for long tours in poor conditions.
High quality steel frame, super strong 26" wheels, decent freehub based drivetrain, large profile tyres etc.