The pyramids weren't built as a way to service the pharaohs into the afterlife, they are tombs.
But there is a direct connection to the structure of the pyramids, and the constellation of Orion, which is part of the true story of the 'birth of christ'. 3000 B.C. the Egyptians worshiped Horus (born on dec 25, followed by 3 kings, and a star in the East, was a teacher at 12, began ministry at 30, betrayed and crucified, died for 3 days was resurrected, and you can do your own history lesson on that, Jesus' birth was NOT an original story, by historical FACT) but this was derived from an astrologically phenomenon; On dec 24 Orion (also known as the 3 Kings) lines up with Sirus (the brightest star in the east) and points to the sun rise on Dec 25. (the birth of 'god's sun'); also the sun fades into south, appearing farther away from a location, and then stops, stays still on the horizon for 3 days in the constellation of the Southern Cross (Crux), then moved back north again (died on the cross, dead for 3 days, then resurrected)
This of course is all condensed, but you can pursue this to be fact on your own.
Now, the 3 pharaohs (kings) were placed in tombs mapped out to mimic the 3 kings of Orions Belt.
It's an astrological occurrence, and on purpose (the Kings would accompany the 'god's sun' in the sky, they wanted to reflect the 3 kings, the other smaller step pyramids came later on) this was the purpose of the pyramids, not necessarily in service to the after life.

But that will basically point you in the right direction for your answers...

(sorry if I offended any christians, but you guys have been playing up to the biggest lie ever told, and your story of jesus was plagiarized)

According to Mark Lehner:

"The success of an ancient Egyptian in the Afterlife depended on the burial rites and later offering rituals in the tomb. For the king, the pyramid was the place of acension and transformation , His independent modes of being - particularly his ka - stood at the head of the all his living and dead subjects. This was particularly true in the Old Kingdom, when only the king's pyramid was inscribed with funerary texts. No wonder, then, that it was so important to take care of his ka, for in a sense it contained the life force of all his living subjects.

The name of the pyramids show that they were poercieved as places of acension and transformaton, Khufu's was Akhet, the 'Horizon', of Khufu. Built on the work akh, the name signified not just the horizon but the 'radiant place' of glorification."