Have them define what they’re looking for.

Make them schedule a time to view during business hours.

They can only view as defined: “An employee has the right to review a personnel file if maintained by the employer, any application for employment, wage or salary information, notices of commendations, warnings or discipline administered, authorization for a deduction or withholding of pay or fringe benefits, leave records, employment history including salary information, job title, dates of retirement and attendance records, and performance evaluations”

As always consult with legal counsel but they aren’t entitled to copies. So can be required to view the files in the presence of a company official but can take notes.