While I usually eat the skin of a baked potato, I prefer mashed to be silky & buttery, with no trace of the skin/peel. I use a KitchenAid stand mixer; first with the paddle, then the whisk.
I've also come 'round to the notion of making mashed potatoes the day before and re-heating--in the microwave, preferably---or a slow oven. As I've gotten older, I do as much as I can the day or two before a big event. That way I'm not slammed in the kitchen on Thanksgiving or Christmas. I get to enjoy the day, too!
I always make the family's Thanksgiving meal and transport it to my nephew's house in Minneapolis. We reheat everything--turkey and all--very gently and the results are excellent. The house is perfumed with all the usual Thanksgiving cooking scents, but no one is slaving over a cooktop full of pans. It's almost like having the meal catered.
The one exception is the ham (I always serve turkey and ham on holidays), which is baked on the day of the event; although it does get sliced, panned, and glazed the day before.