I've got 90cm of free space under my table. That's convenient when you need to sit underneath it to repair or install something. The frame is 7cm, so the lower (hidden staging) area is at 97cm.
On top of that, 15cm higher, there is the station etc. at 112cm. I find that a nice height for viewing while sitting on a stool, and for working on the layout while standing. It's also out of reach for my youngest child
One mistake I made with an earlier layout is to put it too low, making it very hard and uncomfortable to crawl underneath. And I can assure you that you need to go there every once in a while.
About storage: I've put all my train stuff in boxes under the table. Hardly any room left. In my opinion, it's not a good idea to store a lot of stuff there, especially in the building phase, as you have to move it around all the time to reach certain areas. That's a true demotivator!
David.
