The top 2 floors of the castle are called 天空の白鷺 or "Egret's Eye View" in English. It's not a direct translation, but a unique play on words from the phrase "bird's eye view" since Himeji Castle is often called the White Heron or White Egret Castle. The top 2 floors of the scaffolding, the 7th and 8th floors are open to the public for viewing. It is recommended to make a reservation online so that you can go up the elevator without waiting, but even if you don't have a reservation you can probably get up there without waiting too long. If you go during cherry blossom season however, I wouldn't go without making a reservation. The online reservation system is fairly straightforward and can be found here: Egret's Eye View Individual Reservations.
On the way to the main keep, the inside of the Ri Watariyagura is open to the public. Normally, this yagura is not open at all, but now they have a nice exhibit of some roof tiles, old shachi and an amazing collection of armor in the corner. This exhibit is a must see. Once inside the main keep construction area, there are some exhibits about the restoration both on the first elevator floor and also on the 7th and 8th floors. Be sure to view them all. There are some really interesting things here that you aren't likely to see again.
On the 7th and 8th floors, there is a large glass window through which you can see the main keep and the in progress restoration. Each floor is also playing some fascinating videos about the repairs. Currently, the 8th floor restoration is nearly complete so there is not much work to see, but you'll never get to see the karahafu gable and the roof tiles so close again. On the 7th floor, you can see the chidori hafu gable and the roof stripped of all the plaster.
It was a great tour of the castle. I wish I had gone a little earlier before they replaced the roof tiles on the 8th floor too. If you're interested to see the "bare" roofing or walls of the 7th floor, I recommend you go soon. I should have taken a few more pictures of the scaffolding to show how it's set up on the grounds, but maybe next time….