I'll start off by admitting that I'm just a bit biased, as I live in Sonoma County. But look past that.
Presently, the plans for a road to travel around the back of Flick's Fun Fair to Carsland are very awkward. My idea is to do away with Flick's Fun Fair and Bountiful Valley Farm, and build Sonoma Square where Bountiful Valley Farm is. I would use only about a third of Flick's Fun Fair for the transition between the three areas (Sonoma Square, Hollywoodland, and Carsland).
Here is a visual:
The service roads have been re-routed slightly, the only change being that one goes in front of the dark ride show building (more on that later).
For Sonoma Square, I have created a grassy park with a huge Oak tree in the center. Along the back side are shops and a quick service restaurant to make up for the loss of P.T. Flea's Market.
The attraction facade has its own street. I'm debating whether to make it mission-style or brick with white accents and ironwork railings. Either way, this is a solution for the Mystic Manor. Whether you get below ground by elevator or a more original way not used in the Haunted Mansion, it will bring guests underground to cross under the service road and into the new show building that takes the place of the ITTBAB building. Because of the relocation of the service road, there is about as much space as there is for TLM.
Yeah, the map is a bit off. But you get the idea.
Anywho, The hill adjacent to Carsland and ToT serves as a backdrop for Sonoma Square and, on the ToT side, for the Hollywood Tower Hotel. The trackless ride show building, being sunken, would lend itself to any shaped structure above it, so it would also be themed to a hill and would blend into the overpass of the pass over the service road. The larger hill next to Carsland would also be a large building for backstage or a future attraction.