When the FAA put temporary flight restrictions in effect they can make the ceiling as high as they want. The airspace around the airport is controlled airspace so they don't need to worry about that. Under normal conditions, if memory serves me, the Airport Traffic Area extends to 5,000 feet, but I could be wrong. It's been awhile since I had to think about it.
Don't know about now, but in my day the area around the airport would be considered controlled airspace, even if the tower was not in operation at the time of the accident. An airport is controlled airspace by virtue of there being a published instrument approach for the facility, not the presence or operating status of a tower.
Actually, it's VERY involved and if you're not dealing with the regs on a regular basis it's easy to have missed a serious change in the requirements.
Right you are. I think that the prohibited areas over DC and restricted areas over top secret military areas like Groom Lake are of unlimited ceiling. If you're not in orbit, you can't fly over them at all.
-ccm