To prepare the macaroni salad:

1. In a medium saucepan, cook pasta according to package directions. Drain pasta, and rinse with cold water.
2. In a large bowl, combine mayonnaise, milk, vinegar, mustard, sugar, salt and pepper. Add macaroni, celery, green pepper and onion. Toss to coat. Cover and refrigerate.

To prepare the home fries:

1. Using a colander, rinse potato cubes with cold water and drain well.
2. In a large skillet over medium heat, melt butter. Place potato cubes in the skillet, and stir to coat with butter. Season with salt and pepper, to taste. Cover the skillet with a lid and cook for 10 minutes. Remove the lid, and continue cooking while turning frequently until the cubes are brown and crispy, about 10 minutes.

To prepare the beef chili:

1. In a large skillet over medium-high heat, combine the ground beef, onion, bell pepper and minced garlic. Stir until beef crumbles and is cooked through, then drain.
2. Place beef mixture in a slow cooker. Stir in kidney beans, diced tomatoes, chili powder, salt, pepper and cumin. Cook on low for 5 to 6 hours.

To assemble the Garbage Plate:

1. On a large, sturdy plate, scoop a generous helping of macaroni salad. Add an equally generous helping of home fries. Top with two cooked beef patties coated in melted cheese.
2. In a small bowl, combine the Dijon mustard, horseradish and sour cream. Spread onto the burgers. Ladle a serving of beef chili over the top.