|Surprisingly the data may still be readable. Depends on how and where they were stored. |
If the data is important it shouldn't be that great a task.
The real key is a BIOS that will still recognise the 5.25 1.2M drive. As Stuart already said, without that you will be out of luck.
There are plenty of folks (packrats) that still have those drives and cables lying around. I'll bet DAVEINCAPS can fix you up.
Cable should be easy. The older cables all had the connector for both. Many had two connectors for each as many would install two 5.25 drives to duplicate disks.
The other problem is the head alignment varied from drive to drive. If the drive used to make the disks had a head slightly out of alignment the drive could write and read disks OK but those disks might not read well on another drive.