I have a build for you.
Workstation Activity Stations work again, and may be purchased from Guests again.
Miysst, Batteries and Such now are a separate “Character” save. Hotel save has everything else. Your Character follows you in multiplayer while your Hotel is something others join.
The multiplayer upgrade tweaked with most things, so everything needs to be touch tested.
Go have fun, if you break it let me know 
Note:
Multiplayer does indeed run locally if you run two (or more) copies of the game. I need to work on getting the replication to be “lighter” as it seems the game is a bit bogged down (only when loading) when there are 4 players. I’ll keep hacking at it, but I’m pausing on MP for a bit to get other systems in place sooner rather than later. Feel free to ask questions.