I'm not familiar with peach wine, but I'll offer some basics. Many of the problems you'll encounter in wine making come from oxidation and non-wine additives. During primary, oxidation is not a major concern because the wine is protected from the air by the layer of CO2 given off during fermentation. Much of the non-wine "stuff" included with the peach juice during primary will fall to the bottom of the bucket, called "gross lees" and will be racked off when going to secondary. SO, you shouldn't keep the gross lees in the bucket with the wine for more than a week or so. Also, once you loose CO2 protection you won't want a lot of air in the bucket and should rack to a smaller storage piece. In short, I wouldn't go past 2 weeks.
Tony P.