Hey rplst8......I am looking a lot of track passing over top of each other. Wow. Keep clear vertical separation between layers around 7" or more to get your hands and rolling stock underneath each level. I will temper my comments with the fact I am 65 years old and walking on layouts or climbing underneath is just not a good design option for me anymore.
I would still recommend that each and every switch be accessible for maintenance, either to replace if necessary or change out a switch motor, if electric.
Please keep us all updated. Thanks.
Donald