Gold has one or two extra mansion rooms, iirc. And yes, around 1 in 3 mansion rooms you'll get a "Cousin It's Hideout" award, which can be points, Extra ball, etc.
The cousin it awards kind of make the scoring a little nuts. Over a really good game they can easily add 100 - 200M to your score.
I'm almost certain you can put gold roms in a regular TAF if you really want to see the changes.