You can freeze potatoes, but the trick is to only blanch them. I would get 50 pounds at once for a meals for the homeless group I volunteered for and a friend and I would spend a day getting them ready.
- peel and cut the potatoes into about 1 inch cubes
- drop them into boiling salted water for about three minutes
- take them out and immediately shock them in ice water for another three minutes or until cold
- dry thoroughly on towels (or paper towels)
- place on trays and freeze for about an hour and then bag in the amounts you want.
- When ready to use, drop them into salted boiling water again until done as desired.
- At this point they can be mashed or served as is.
This is a tried and true method. Hope it helps!