It sounds like, based on the Office Customer Preview, Microsoft has done the bare minimum to say that their Office 2013 desktop programs are touch enabled. See this Ars Technica article, "Why bother? The sad state of Office 2013 touch support." According to what they're saying, with that busy ribbon bar only minimally modified to operate with fingers, and the settings dialogs not at all, it will be an exercise in frustration to try to use Office using only a touch screen. I guess you're really going to need that keyboard and trackpad on the Microsoft Surface.