Good advice, in all directions, John.
My aborted 'dangler' did in fact have a 4-pulley arrangement.
I never quite got as far as the legs, but learned enough to swiftly realise that they would be a highly desirable next step! Although it may be said that the ability to easily shove a suspended board around in mid air enabled me to get away with much less access clearance round all four sides. Huge boards don't dance around much - inertia makes them sway fairly gracefully! No, NO NO!!!! I must not overdo it next time!
If I had continued, I feel that safety considerations would have required sturdy removable cross beams for the board to rest on in the raised position. I then developed the idea that the same arrangement and beams could probably be used in the lowered position also - no dangly legs at all. Different working heights could be accommodated fairly easily by installing different wall mounting cups in which to firmly and safely rest the cross beam ends.
Perhaps by the time summer comes around again (it seems a heck of a way off right now!), we might all jointly arrive at an idiot-proof, practical and reasonably inexpensive design that does the job and doesn't actually kill anyone!
John's comments on the flip up model are also making me think again about that one. A slim shelf down one wall of this one's bedroom would be a real possibility. No reason why several trains could not be 'driven onto sidings there, hmmm . . . that layout still actually exists, though it has spent the last few years in store. Too many unfinished projects!