Basically, you can make your mac salad the way you normally do, with this variation for the dressing:
Onion powder (because I don't like raw onions)
Knorr Vegetable seasoning mix (the kind you use for spinach dip)
Salt and pepper to taste
In a small bowl, combine ranch dressing and mayo and stir until it's blended well (I never measure so you'll have to eyeball this a bit).
Pour in the vegetable seasoning mix (for a large bowl you can use all of it--smaller portions only use about half), salt, pepper, and onion powder.
Mix until it's well blended.
Spoon dressing mix into bowl and mix until everything is covered well.
Chill in the fridge for a couple hours and enjoy!