It was a lot of work moving carpets out of the way, drying those that got wet and preventing the water from coming in.
Once we got it all dried out I saw someone selling the contents of a dance studio and I asked if they were also selling the floor mats - they were, and so I bought 800 sq feet of used flooring.
Again, it was a lot of work moving everything about to access the entire floor but it progressed well.
Once that part was done, I moved stuff from other parts of the room to expose the floor elsewhere...
Green areas indicate layout viewing areas, blue where layout will be and yellow is for storage areas.
The foam mats provide a very nice soft layer over the concrete floor!
Update: my train friends love the floor and many have gone home and installed something similar. I regard this floor as the best thing is did in terms of room preparation. It is so comfortable to work on and when things drop they are less likely to break.