Yes we did need a permit, we picked it up on the way in a small place (maybe el kharga) just before the track started. no details sorry, I was tagging along with 4 germans on bikes who had planned it.
this was in Jan 93! so a road may be there now.
Im sure there's plenty more info out there.
eg sahara overland book?
have a good time POB in the sinai.
lunch+ snorkling at the blue hole (dahab)
a PADI diving course in Dahab
diving the wreck Thistlegorm from Sharm.
off roading anywhere on the sinai!
PS checkpoints to/from cairo may try and ask you for papers you dont have.(imaginary papers) I just waved my carnet at them and looked confused.
PPS its easy to lose your egyptian number plate. they will fine you on leaving egypt if you do. so double/triple tie it down.