Jacey, nice to see you are still here, many aren't after this length of time. I'm having a little chuckle here as when I originally read your post, my first thought was "move house", but I didn't want to sound so rude as to say so. It reminded me of my first house which was at the flat end of the street but the other end was very much "mountain goat territory" and the driveways reminded me of yours. After living in the homes for years, some spent mega amounts removing rock and excavating to create a garage more at road level and from there the stairs started zig-zagging to the front entry, new front entries were even created at a lower level, but the stairs still continued inside the house, there was just no escaping the climb. I wondered how you even got your wheelie bins up and down the drive. Hope you are enjoying your new home, long term I think you made a very wise decision.

with the native trees next door i'm wondering what you mean by formal?? some native shrubs like like correas or westringia or big strappy plants like dietes, lomandra, dianella can be made into a formal looking garden but check with your local nursery to select most suitable plants for your local climate and make sure you prepare the beds and watering system before buying any plants

Assuming north is what you're indicating it's really poor planning putting a garage hard to the boundary on the north side and the majority of bedrooms on the south. Are you sure this is correct as typically north is up the page as drawn. If so the whole thing needs to be flipped/mirrored. Also there's arguably a significant amount of passage space in the house plan for what it is, not to mention a lot of unusable external space to the sides of the house. An alternative and more efficient design/floor plan would utilise the available space better for you and give you more flexibility with what you're trying to achieve....You're possibly pushing the envelope for what you're wanting on a single level for this particular proportion block of land. There would be a 2 storey option, (say with Master Bedroom on upper) which would achieve a double garage and all the other requirements, but appreciate it's always about practical cost limits. 6m to the back fence from the alfresco is not huge for a family home but depends upon your lifestyle. I'd be considering reducing the building footprint and really the only way to do that for a house this size is to consider a 2 storey format

A few points. 1. Although the top of a hill seems like the ideal location you will be buffeted by winds on the peak. Better to site the house about 100m below the crown of the hill. You will still get the views but importantly be sheltered from weather while still being situated out of the cold valley. While wind may not sound too bad, you'll be surprised how much more difficult this will make gardening especially in the environs around yass. The earth there isn't very water absorbent so all your watering is going to run off leaving your garden dry and then the wind will be extra dehydrating and harsh. But siting on the slope, yes you will need to terrace but you wiill also benefit from runoff further up the hill. 2. With a drive that steep you are going to need asphalt. Compacted road base and gravel will just wash away in the first heavy rain. A dirt road will also be suspectible to erosion and minor land slips leaving deep fissures in the shoulder. 3. You are going to need proper runoff mitigration as soon as you cut a path up the hillside you are simultaneously creating a way for water to gain velocity and force from runoff. I would consider gabion reinforcement on the embankments or at the very least plants of either lomandra or vetiver (deep rooted grasses) to slow water down as it traverses the hill side. These grasses will also capture leaves and other debris preventing it from becoming dangerous in a storm. To be honest it will be worth you engaging an engineer to design your drive including run-off management and whatever other reinforcements you may require. If you wait until you have a major storm and your drive becomes unpassable it will be far more inconvenient.