Part of the reason The Haunted Mansion ride works is the isolation you, as a rider, have from the other guests, despite hundreds of tourists sharing the same conveyer belt system. It allows you to focus on the atmosphere of the various sets and helps to keep noise to a minimum, plus it just feels creepier to be "alone" while travelling through a haunted house.
The best way to duplicate that in a restaurant setting would be to have a layout similar to Walt's at DLP. A series of smaller parlours with interconnecting hallways to give you the sense of an actual, (once) functional house. Have a music room, a library and conservatory, a "balcony" overlooking the grounds/graveyard etc.
The WORST thing they could do, is something like BOG. Big, open, convention-hall like spaces that look absurd in scale and allow the noise of children running around to constantly echo, ruining any sense of atmosphere.