To generate the list of files that poly uses when building HOL, try
something like

    ../bin/unquote < ../src/bool/boolScript.sml |
       ./genUseScript --hol /dev/stdin > usethis.ML

Follow up with

    poly --use usethis.ML

to get into a Poly/ML session with that early prefix of stuff built.

To handle something like pred_setScript and to do it one fell swoop, the following should work:

   (../bin/unquote < ../src/pred_set/src/pred_setScript.sml |
       ./genUseScript --hol /dev/stdin ;
    echo 'use "../src/pred_set/src/pred_setScript.sml";' ) | poly

and will deposit pred_setTheory.{sig,sml,dat} into your developers
directory.