I knew someone that had a refrigeration repair and second hand shop. Years ago he gave me a few tips. For the door gasket take a piece of paper and close the door on it. If you can pull it out with very little or no resistance use a hairdryer to heat that section. While heating you must pull on it holding it out until it gets hot. Then hold it until it cools. This should help make the gasket make a good seal for about a year. If your refrigeration unit seams to be continuously running the most probable cause is wet insulation. He would actually place a dehumidifier inside for a few days to pull out all of the moisture.
