In the first photo I think it looks good. I can believe the forced perspective and therefore believe that the motte is bigger than it really is but more distant. I also like the winding path - it left me in no doubt about what I was meant to be seeing. Perhaps you can enhance the illusion further by de-saturating the colours progressively up the motte when you come to do the scenic work.
The other viewing angles reveal the reality but this is as expected since they are not the angles from which the forced perspective is expected to work. I am not sure what you can do about that. Even if you model less of the motte and push more of it to back-scene, you will still not get the correct impression from these other angles since back-scenes only work properly when viewed face on. The best forced perspective models I have seen control the viewing angle very precisely to a specific point through a proscenium arch. That is not really an option with this layout. Nearly all of us are forced in to difficult compromises due to space
On a more general point, I think your buildings and track look really good.