Bring approxiately 4 quarts of water to a boil and add the macaroni. Cook until VERY soft, about 15 minutes.
Drain the macaroni and return to the pot. Add the 1/4 cup vinegar and stir until the macaroni is well coated. Let cool.
While the macaroni is cooling, combine the mayo, milk and brown sugar. Mix well. Add any desired salt and pepper.
Pour this mixture over the cooled macaroni and mix until well blended.
After mixing, add in the green onions and carrots. I usually save a little of both to add as a garnish on top.
This salad is best if chilled for 2-4 hours before serving.