i really like the game, and the art style. I'm looking forward to seeing future updates!
As others have said, I'd love to see some additional ways to waste time. Perhaps more books, if nothing else right now, just as a time trigger, and maybe later useful for other things. Also, perhaps the ability to play with the dog, clean up the horse stalls... those could work for time wasting, or increasing of other stats. Maybe older sis sees you doing hard work, getting all sweaty, and that could help increase arousal... but it also puts multiple time wasting triggers around the map, so that way no matter where you are, you could trigger a bit of a time spend.
Also, again, as others have said, perhaps more ways to summon/unsummon the ghost. Maybe the graveyard outside, or some statue or personal effect left over in the library, could be used to bring him.
Keep up the good work!