The Chapter House building guidelines say that "Each location must include Regio as a Minor Boon or Minor or Free Hook."
The Minor Boon (Covenants, p. 8 ), which I took for Guiverna's Quarter, says: "The covenant is located in a magical regio that can be entered in many ways. The covenant may take measures to limit entry into the regio, but these are never perfect." The Minor Hook (ibid, p. 10) says: "There is a regio on the covenant site, although the covenant does not lie within it. The magi do not know everything that is in the regio." I couldn't find a Free Hook for Regio in the book. The labs must also take Regio (ibid. p 119) which says: "The interior of the lab is in a regio, and there is another regio level, which the owner can navigate easily." Which, I guess, means that by definition the regio itself must have an Aura at least 1 less than the Lab (in Guiverna's case, her Lab has an Aura of 3, so the Regio would have an Aura of 2).
The guidelines also say that "All points are linked by a regio network."
My understanding, interpretation, what have you, is that each Quarter is a Regio. And that each Regio is connected by a Network, the "hub" of which is the vis-producing fountain at Sa Dragonera. Neither the rules or guidelines seem to say that the Regio has to be small (the size of a house) or huge (the size of the Nile Valley)
I was picturing Guiverna's regio as being a few miles across, at most (probably three or four, maybe five). Under normal circumstances, it probably wouldn't take more than a few days to thoroughly explore, but since it would probably take time away from any other seasonal activites (i.e. lab work), it would have to be a seasonal task. Unless she were studying that season, spent a month exploring, and took the -1/3 hit on her SQ, which is an option that just now occurred to me.
Tl; dr: seems like we read the same passages and had two different interpretations of it.