These documents are not personal property. They should not be at personal residences, period. Clearly it’s a widespread issue and the system needs to be reformed. Either classifications have meaning, or they don’t.
In a less hyper-partisan time era, the proper response would be a formal government review and overhaul of how classified documents are handled – how/why classification happens, declassification, tracking & recovering documents (especially in the hands of elected officials and others who are allowed to handle them outside of secure locations).
Having said that, I think the G-men are going to need a backhoe to recover the classified documents Ronald Reagan lifted.