I remember reading a few years back that Ms. Horne (actually Ms. Fenn) was to be getting her own spin-off from Twin Peaks set in Hollywood, and Mulholland Drive was "supposedly" going to be about her new life as an actress..."supposedly".
I know it's probably just a rumor but let's think about it for a moment, at the time (circa 1990-1991) the hype "could" have been there, if the interest was there (from fans and most importantly network execs) then Audrey very well could of had her own spin off set ala Mulholland Drive "supposedly". Now there is no concrete proof that that was the plan, what I recall reading (I'll post sources once I find them again) was that Lynch was interested in doing a new series focusing on the Audrey character, what killed it I think was A) the cancellation of Twin Peaks, and B) I don't think Fenn was interested in it iirc.
So let's say that everything was a go for this new Audrey spin off, the timing would have been pretty good all things considering with the Billy Zane character coming to whisk her off her feet, her talking about going to Hollywood - the time of her departure and supposed destination and goal would make sense for the spin-off if it were really Mulholland Drive. Now obviously MD pilot didn't begin production until 1997 - 1998 the earliest, and wasn't finished until 1999 where it was rejected and subsequently turned into a feature film for a 2001 release.
Now *IF* MD was in fact supposed to be Audrey's show, there is a considerable gap in time between the ending of Twin Peaks and the Feature Film. We learned that Lost Highway is supposed to take place in the Peaks universe yes? The Mystery Man is to be a Lodge Spirit of some sort? Perhaps Lost Highway could be used to bridge the two parts together. LH could possibly have originally have been the basis for the spin-off (obviously omitting Audrey and the Billy Zane characters), the second half of the film takes place in California - a wild nightlife is seen, doubles of the same woman are also seen, I think this could have been part of the big mystery/main plot for the beginning of the Audrey spin off where she would arrive in town, starving for work; meet this young mechanic and falls into a strange twist of events surrounding two women who are apparently the same, a man named "Dick Laurent" and a mysterious man in black.
The MD stuff could unwind gradually - I've always pictured Betty as being the Audrey Horne character if it were ever really meant to be the sequel Lynch had talked about back in the day. Camilla/Rita would have probably been the same character, amnesiac actress - and this would lead Audrey deeper and deeper into events that she has no control or idea of that gradually spiral out of control (the Castigliane Brothers, Mr. Roque, the Hitman, and the Bum). I think It could work as a way of showing proud Audrey that it is not as easy to make it in Hollywood as she might think, and seeing amnesiac actresses' character would elaborate how she might not be ready to be a star yet.



