Well... you could do drag and drop or open the files (depending on type) right off of the drive. I would recommend using the "Accounts" setting when doing this however. What generation Extreme is it?
By dragging and dropping I didn't mean locally/from a computer which has the actual drive attached to it; I want this to be almost like cloud storage but be local in my house. (I don't want some bad cloud service, esp. on old PPC Macs). I was thinking I would save my current documents to the HD and then, from now on, copy new ones I make, to the drive.
(I have an Airport Extreme base station with a copyright date of 2005). With permission, I may be able to use one of our newer devices.