You already got so much great advice, I don’t have much to add besides:
Someone suggested something about parchment paper and a hot plate. I think it must have been some sort of typo or other error. I’m a big fan of parchment paper and shelf paper all over the place on Pesach. And a hot plate can be a good idea. But DO NOT put those 2 items – Paper & Hot Plate anywhere near each other, for any reason, b’shogeg or b’meizid, EVER.
Also, clearly the best potatoes for karpas, if you can get them, are Yukon Gold. But if you want that nostalgic ‘in der heim’ flavor and you’re not going gourmet, any humble brown-skinned spud will do.
And finally, You may want to keep in mind that the first Seder falls on Friday night this year. It’s always best to have all simanei ha’seder prepared before you light candles. This year it’s even more important! Peeling and grating and chopping and even preparing the mei melach create all sorts of Hilchos Shabbos issues. And you won’t be able to cook your karpas potatoes, if that’s what your family eats for karpas. And even if you prefer a radish, you’ll end up with a raw egg and an unbroiled z’roa on your ke’ara.