Michael- The yard and spurs on the upper level look good.
I agree with NECRAILS, access to get at that double cross-over is a must.
I'm a tall guy so I prefer a higher layout. Raise it up to what feels comfortable to you. Remember lots of bending over while building. Access underneath for wiring is often overlooked too. It depends on your audience too, small kids would need step stools if you raise it.
For the height of the upper level, measure your tallest equipment including the track and adjust accordingly. I think 7.5" is a bit high but depends on what you run. If you can lower it then the grade will be easier for long trains to pull. Watch clearances on curves and check as you go.
Definitely a solid plan and a great start.
Bob
