Anyone have a walkthrough for rank 4 guest?
No walkthrough as such. Basic ideas stay the same as before, and you will have to reach the maximum in level 4 with your employees to satisfy each and everyone.
Since I guess you're having problems with Sophia, and maybe the nun whose name I always forget: Sophia is a female dog. You really need everything to satisfy her: improved rooms, items, and cards. If necessary you need to switch them around every time.
Improved rooms you just get with clicking on them and upgrading them, that's 5 points.
Items: search the mansion in the morning or afternoon (there's one for each service).
Cards: satisfy (other) customers and visit Isabella once you collected enough points to get them.
Need to equip everything with the girl in charge.