MOD UPDATE:
Due to life today I am getting a late start on trying to complete all the backporting of Runey's changes before I can even get to the process of updating the WT part. If I had to guess on an ETA it will be Thursday even my time at the earliest if not sometime Friday. My apologies but life is what it is.
Also if you'd rather me continue my mod instead of using Lain's upcoming version then please give this post a Heart so I can see if I should continue or not.
At current point, i'm think good approach it is make own version (fork) of the mod - throw away "backward compatible saves" and assimilate the best Lain's additions, navigate and play Harem Hotel efficiently incredibly hard if target is only story. So this mod alleviate the painful adventures with checking the text walkthrough, going back to game... back and forth. So what you took - hero work.
This time Runey returned to much earlier stage in its game and seems going continue "outside map" mechanic add here & there... making previous progress invalidated - so trying keep oldier saves, ignoring new mechanic is might be harmful.
So basic needed features:
1) Walkthrough menu like already implemented for every character which hover above game ui at any place.
2) Of course cheat menu. Probably with more commands, such as change characters stats. Through MC's PC seems kinda limited list of cheats - such as "jumptoend" handy, but useless in own full playthrough.
In my opinion this most important features - everything else is nice to have.
Pretty sure if you can - you probably want to avoid any spaghetti code in your work. Dunno.