Just pointing out, that a pressure cooker is not the same as a pressure canner.
My sister makes the fancy mashed potatoes with cream cheese and sour cream at Christmas time. She will prepare the recipe and freeze it. When it thaws, it looks a mess, but a quick stir and everything looks great again.
Also, I have made and froze twice baked potatoes for our kids when they were in college. They loved them, and they keep asking for them.