Any point leaving Butternut out longer

So have avoided any frosts so far and have brought in some of my butternuts, hedging my bets, but the ones still on the plot aren't a nice tan colour, more pale yellow.  Should I just get the rest in now anyway and try and ripen them inside? Don't have a greenhouse and no south facing windowsills.  Have put the ones I've brought in under a velux window in a warm place.  First time I've had success with butternuts so really looking forward to having them all winter!
Cheers.

Yep, got the rest of them in today.  Fingers crossed.  It feels pretty cold tonight.   

No they won't grow any more, plus the weather set to change to much colder after Tuesday.
Any that get frosted will turn to mush