I pass through the station on a daily basis, and since January the rate of change in the station has been incredible. It seems that every week some new bit of scaffolding as appeared or some bit has been removed.
Currently work is ongoing to replace the floor. The work is happening in a odd piecemeal fashion with what appears to be random sections being fenced off and dug up and replaced (no doubt there is a some master plan that makes sense somewhere - probably based around the need to keep the station fully operational at all times). You will certainly find a mosaic of old, new and temporary plastic flooring in place. The new flooring is made of very large rough marble tiles that give considerably better grip in wet conditions than the old flooring.
Most of the Eastern side of the roof is done (I get a grandstand view of that side of the roof from my office) - with just a littile finishing work being carried out and some of the temporary roof has been removed in the vicinity of the Calton Road Entrance and the ends of platforms 2/3/4 making an amazing difference in terms of light. Work seems about to start on the West end of the roof, with lots of new scaffolding and fencing appearing over that side of the station.
The bridge over to Market St and the access to platforms 8/9 has been removed, and there is currently an enclosed temporary bridge built from scaffolding (not that you can tell from the enclosure) which leads to temporary stairs to 8/9 and a temporary exit to Market St al little to the west of the original. It is currently possible to see the steel superstructure of the new replacement bridge and platform access being built from the Market St Entrance.
As others have mentioned the Waverley Steps are open and the temporary access to the Princes St mall has been removed. They are currently experiencing teething problems with the escalators with at least one unit out of commission and being repaired on a weekly basis. There is also a pretty nasty drainage leak in the in the temporary joint between the new roof over the steps and the old roof which forces them to fence part off in heavy rain.
So yet it has changed loads, and will probably be different again by the time you go through.
Said lounge is pleasant (the cleaner is a lovely Scottish lady) - with a coffee machine, still/sparkling water, crisps and biscuits. Can be worth bagging a couple of snacks in case the catering on the way down to London leaves you hungry.
