[smhenderson]

Despite the potential inconvenience I would suggest airgapped + sneaker net is a far better option for anything running XP at this point.

How hard would it be to put a supported windows on the network right next to the XP box and transfer files via flash drives?

[jessaustin]

One would have to enforce this, because it would be quite tempting to simply switch the network cable from the new box to the old one. Users DGAF.