I'm sorry to necro post but after all the trouble I had searching for the same thing (walkthrough) and eventually finding a copy, I was disappointed that the walkthrough was actually incorrect in several places and was rather in-efficient in structure, so I ended up making many changes and redoing the walkthrough for myself, just on principle.
As noted in the walkthrough I've attached (Just in case someone else tries to search for a 'working' walkthrough for this game in the future):
Modifications include additional save points to decrease as much unnecessary repetition as possible. In addition, un-needed route instructions for getting an elusive Mikado CG were removed to avoid confusion, as those directions simply did not work, but the options that DID work (after much time experimenting with choice variations), I incorporated into the Yami & Mikado route. Also, the ‘Run route’ didn’t really need a separate ‘from the beginning of the game’ listing as in the original walkthrough so it was merged into another existing route to avoid more unneeded repetition. Also, some minor corrections made to *should save you* events to show who should actually be the one saving you there on a given route.
(I had to 'rar' the file because *.docx files (MS Word 2010 ver) are not allowed to be uploaded here for some reason)