While you've already seen a real-life mockup, here is a satellite style view showing a few more of the planned details.
The structures are all shown in brown (from the left: factory, station, bridge) with the road surface in grey (I'm not quite sure how the road surface will wrap around the station and platform yet). The grey line running across the layout shows the horizon (i.e. where the vertical sheet for the sky will fit) and as you can see the tunnel mouth (on the left) will be in front of this to allow hillside above the tunnel, while the road bridge will sit snugly against the horizon. The numbers on the track represent the height, in cm, that section is raised above the baseboard. While a maximum height of 2.5cm might not sound like much it represents a 4% slope which is quite steep for a model railway, and way steeper than any real UK railway.
I'm sure this plan will evolve as I start to build the landscape but I think it's a good point to start from.