Garage/home walls have to be fire rated. It would function better if the garage was set apart from the main house with either a courtyard or breezeway between the two so that you could get more natural light into the house and still be able to utilize the visual connection between the two. A garage that needs to house two cars stacked on a lift will need to be taller than you are planning to account for not smashing the lighting on the ceiling. You might want to house something beyond lower height sports cars. Our 4 post lift in our garage won't allow a tall vehicle like a SUV on it and then raise to full height, and we vaulted our already 11' tall ceiling to 15' in the lift bay. Even with Corvette stacked on top of Corvette, it's really tight with the lighting when the lift is up enough to get that second vehicle under it. Only Formula cars without the wings would really work to have the double stack be comfortable at that height, and they have issues with the ramps, needing longer ones to get the ground clearance for the chassis. We also climate controlled our garage area, as that keeps the vehicles in much better shape, and it's a much more pleasant working environment. While you plan on having guests here, this isn't a very guest friendly house. There isn't enough room allotted for them, either in the public or private spaces. I might suggest the separate garage have a second floor guest suite(s) and make the main house more about your groundfloor space on one side, and the public space on the other, linking to the garage space visually through the breezeway. Double height space is very difficult to heat and cool, so I would suggest having hydronic radiant floor heating for winter comfort so that the people in the rooms are closer to the heating source.(We did that in our garage, so if you happen to need to be on a creeper under something, you don't have a giant cold mass of concrete sucking the warmth out of your body.) For summer, if you rarely get temperatures above 85, then I probably wouldn't do AC at all since you are in a low humidity climate. I would focus on doing some type of cupola with operable vent windows that will allow the hot air that rises to be vented externally. That's an old fashioned technique, but very effective in climates that don't heat and humidity to need full time AC. Overall, you really need a good architect to take these ideas and make them more functional and designed specifically for the site, to take advantage of it's positives. You will need that anyway for permitting, and in CA there are plenty of creative people who would love to be a part of an interesting build. Take a look at some back issues of Architectural Digest and see if you come across any designs that you like, Then contact a couple of those folks. This needs a large amount of technical expertise to wade through the red tape of building and permitting. So, you need someone local as a builder, well as an architect whose work you admire to work as a team to accomplish this build. Hire good people, and then listen to them. A good design is an interactive experience that makes the work better. Good design is "invisible" You don't even notice that things are where they need to be and work the way they "should". Bad design is obvious, especially if you live with it. It makes life harder. Don't make your life harder!

Having a 'friends' entry and main entry seems like a sweet idea, but the reality of it, does it work? For me, the only people that come to my house are friends/family/neighbors and the UPS guy. Therefor the only person using the 'main' door would be the UPS guy, but even then, if there is any question in his mind what the front door is, he'll go to the closest and most easily accessible door. I also completely agree with comments about the foundation plan (general rule, the more corners = the more expensive). While I am all about adult privacy, it is a very long distance between where you plan to put a master bedroom from what I assume will be children's bedrooms, a trek that might not be fun at 3 am when trying to get to a screaming baby or when you are putting the toddler back to bed for the umpteenth time. Just some food for thought :) Good luck and have fun as you continue working through the process!

I'll second the idea of extending the porch across to the garage; otherwise, that empty space between the porch and the garage will seem awkward. I don't like the garage at all: This big and forward-facing, it's going to dominate the exterior of the house. I'd change the door in the master bedroom closet; note that it covers part of your clothes -- you'd have to enter the closet and close the door to reach some clothes. Inconvenient. I agree that another 2' of width in the dining room would be a big plus for comfort. I agree that the mudroom /laundry layout is very nice, even if it isn't convenient to the bedrooms. I'd try to incorporate the pantry into this space ... I don't care for an in-kitchen corner pantry that interrupts the workspace. The biggest thing that needs work though is the kitchen: You've chosen a U-shaped kitchen, a design that's ideal for a single cook, a design whose strength is that everything is at your fingertips with just a turn ... and you've filled it with an island, removing the design's strengths. The island acts as a barrier and reduces efficiency. If you want to keep a U-shape in this area, I'd suggest you go to this type of layout: Yeah, I know, it doesn't include an island, and today's trend is "island at all costs" ... but the shape you have here doesn't support an island. You could

I’d make your pantry door a pocket door- easier to navigate inside the pantry if you don’t have a door in there. I have a walk in pantry like that and the door is open 99% of the time. I would consider bumping the side wall of your kitchen to align with the pantry back wall - as a bonus you’d get more counter space in the kitchen - and then you have a clean line there. I’d also shrink the bathroom by the front door and add in a small coat closet there. Is that bathroom already a powder room? I can’t tell - it almost looks like that’s a bathtub? Not sure. In your dining room - I assume there will be windows along that wall to the backyard but don’t see any. If you don’t have some there I’d add some. Keep in mind though windows along that wall might affect tv viewing with the mounted on the opposite wall, so play with that a bit. Definitely pay attention to what direction your house will face. You don’t want hot afternoon sun streaming into your kitchen. You’ll never want to cook in the summer, ha! Everything else I think looks pretty darn good - but agree you’ve gotta see what this elevation would look like before you go any further. Looks good!