I've found several references to SAD/AD/XAD data types in the HL7 spec, but don't see anything about this info being used to describe facilities, such as those described in the AIL segment (e.g. "2^BLUE HILL FACILITY"). But where, if anywhere, can I expect to get data about that facility, such as name, street address, etc.?
In the PV1 segment definition for HL7 2.x there isn't a dedicated field for Facility Address specifically. If you are the receiving system in this case, you may have to request that data be sent or added in from the sending system. This could be as simple as placing it in the PV1-5.X field (X being whatever subfield the sending system decides on), or adding in a custom Z segment (ZPV for example) to have this data transmitted.
Since there is no standard field for this kind of data in the PV1 segment though, you will have to confirm that the sending system can in fact send this data.