Watched a stupid program about Pyramid construction on Saturday. What a frustrating waste of time. About 2 minutes worth of content spun out over an hour by flash graphics, none of which showed the critical details.
Internal ramps could certainly provide additional access to the lower levels. At those levels, the amount of material is huge so multiple ramps would be vital. But the Egyptians were perfectly capable of building vertical walls and a 2m wide ramp would only need a 2.6m high wall which is not a major thing. So the perimeter would allow the installation of 20 vertical sided ramps. Perhaps it would be more sensible to start with 16. They could be continued to about 48m by which level 2/3 of the volume would be complete.
At that point, the base of the walls reach the edge of the ramp below so some ramps have to be taken out. Reducing to 4 will take us to 90m. That leaves only 1/20th of the volume to finish. 2 ramps can continue to 139m leaving only 0.25% of the pyramid to finish.
Actually, the block sizes reduce as the ramps climb so it might be that they were reduced in width as well as number.
Whatever else happens, it would be necessary to have a crane for the very summit and that means some sort of platfrom wider than the pyramid.