Do the palaces and the Golden Coach belong to the Queen?

No. The Royal Palace in Amsterdam and Noordeinde Palace and Huis ten Bosch Palace in The Hague belong to the State, which puts them at the Queen’s disposal. Paleis Soestdijk in Baarn also belongs to the State.
Click here for more information.

Nor does the Golden Coach belong to the Queen. It belongs to the Crown Property Trust. The crown and other items used in royal ceremonies are also placed in a trust. The Golden Coach is at the Queen’s disposal. The Golden Coach is, incidentally, not made of gold. Parts of its exterior are covered with gold leaf.