One of the benefits of using a Crockpot is that you can walk away from the recipe for longer periods of time and not have to worry about it burning. Unfortunately with Mac and Cheese stirring is usually very important so you can’t completely leave this dish alone for the full cooking time.  However, if you do need to step away for longer than indicated, the dish will still work. You may just notice that some of the noodles cook faster than others so the end result may be varied. You will also notice that the sauce may thicken unevenly, especially around the edges. Finally, some of the noodles and sauce may stick and the dish is more likely to overcook if you don’t stir it. Results will depend heavily on the quality of your crockpot, noodles and the amount of time that you leave it without stirring.