you'll easily get a few days out of it. Butternut is a major staple in South Africa and sold peeled and cubed at the supermarkets in tubs.

to gourmetmama's ? about storing the squash in water - I wouldn't bother. You put potatoes in water so they won't discolor with air contact. Butternut doesn't oxidize like that, so I'd save the space and just chuck it into a ziploc. (IMHO same with the carrots and turnips too - I wouldn't bother with water storage)

The potatoes, turnips and carrots will keep just fine in water for 18+ hrs, in a cool space. My fridge has no room on T-day, I've never tried b-nut squash but..sounds like it would work! Anyone saved them in H2O? .

2-3 days is fine. Just keep it in a ziploc.

I think you could go even longer than 24 hrs provided you keep the cut-up squash in an airtight bag or container in the fridge (I am assuming you're working in a scrupulously clean kitchen, of course). My local farmstand sells peeled, cut-up squash in bags - I asked them when they cut them them up and it was usually 1-3 days before. (I'm a vendor too so I think they were telling me the truth - bet they tell their customers it was cut that day).

i find the best way to store prepared vegetables is to vacume pac them and cook them in the bags in simmering water it retains all flavour and nutreaints and keeps well up to a week

I've cubed butternut squash up to 24 hours in advance and roasted it successfully. (and AntoniaJames, not sure what you're having for your Thanksgiving meal, but the more questions I read about your upcoming menu, the more it sounds like your meal is going to be a major home run! Good luck!) :)

I think you could do it several days in advance w/o any trouble.

I think twenty four hours and you will be fine. Just make sure they are in an air tight container. They will probably roast better and brown up nicely if you in fact roasting them.