The stones of the Great Pyramid have not been subjected to dating methods, as I understand it. Chemical analyses have been conducted, but that's something different. Trying to date the stones is more geological than archaeological, anyway. That's why extensive carbon dating has been conducted on forty-some mortar samples from the Great Pyramid. Being organic in nature, mortar is an archaeologist's friend and is well suited to carbon dating. And the C14 dating that was conducted on the Great Pyramid confirms that the monument dates to the relative date which has always been assigned to it, although it's possible the pyramid is a century or so older than originally thought.
Hetepheres' tomb is not a pyramid but a shaft tomb designated G7000x. It was a concealed burial accidentally discovered by a photographer setting up his tripod east of the Great Pyramid, in February 1925. I don't want to put words in your mouth, but earlier in this thread there was a lot of attention paid to the small queen's pyramid on the east side of the Great Pyramid which is mentioned in the Inventory Stela—the stela mentions the pyramid was made for a royal daughter named Henutsen, so are you thinking of this, maybe? The stela dates to many centuries after the time of Khufu and there isn't even evidence that a royal lady named Henutsen existed in Khufu's court, but that's another debate.
It was in Hetepheres' shaft tomb G7000x where the wonderful furniture was found, so you're right about that. To my knowledge, however, none of it has been subjected to carbon dating. There's no real cause to do so. That the furniture and other burial equipment belonged to Queen Hetepheres is beyond question. Moreover, Hetepheres' furniture represents not only one of the largest deposits of ancient Egyptian furniture ever found, but by far one of the oldest. Even with the tiny samples required for modern C14 dating, it wouldn't be worth it to damage her furniture.
Your question about tests performed on monuments predating the Great Pyramid is an excellent one. That sort of bracketing was indeed considered. In the C14 analyses conducted on the Great Pyramid in 1984 and 1995, many other monuments of the Old Kingdom and Middle Kingdom were analyzed. This includes several Saqqara tombs dating all the way back to Dynasty 1 (Early Dynastic Period). The calibrated dates for Tomb 3357, for example, average around 2900 BCE (Bonani et al 2001: 1312). The conventional relative dates for Dynasty 1 are around 3050-2813 BCE, so in this case the carbon dating seems to be dead on. Several Dynasty 3 monuments were tested, as were several from early Dynasty 4, so the overall testing was well bracketed.
As I like to point out to the alien crowd and Atlantis fans (et al), modern science has corroborated historical research.
The report for the carbon dating can be downloaded as a PDF from this link.