How long should I wait before I lift the lid of my sauerkraut crock?
Don't check on it. 

When I lived in Virginia I used to drive up to Pennsylvania every year to this little Amish farm to buy a gallon of the best sauerkraut I've ever tasted. They showed you how they made it, and I remember the farmer stressing two things: (1) sterilize the jars, (2) don't touch it for 2 months.