To add to the flood of suggestions that are doubtless coming in,
a friend of mine who started a firm that makes big data-storage systems
wrote the reply below in answer to my query about the 58-note catalog.

Mark Kinsler
Lancaster, Ohio USA
http://www.mkinsler.com/

 - - -

A couple of reactions.  15-year-old floppy disks may well still be
fine.  Tossing them would be a bad idea.  I'm convinced there are
people around who can read those disks.  Many of them would hang out
on the Classic Computers mailing list.

Come to think of it, from what I remember, DEC RX01 [8-inch] floppy
drives are IBM-compatible.  And at least one DEC OS (RSTS/E for the
PDP-11) comes with a utility that says it understands IBM file
formats.  So, given that one can find a person with such a system
who's interested in helping out, which shouldn't be all that big
a problem, it would then be possible to run that utility and grab
the files.

Alternatively, it would be possible to grab an "image copy" of the
whole disk, which could then be further processed on a modern system.
Getting the data off a PDP-11 is easy using Kermit or DECnet or any
number of other schemes.