Luxor seems doable from Crete in about a 5hr flight, so enough reserve to fly all the way back to Cairo if necessary, and has avgas. Near Cairo there is just one place that lists avgas: "6th October".
However, Luxor ground temp can reach +50C around the summer months and that is seriously hot.
Alexandria etc is doable from Crete (LGSA) without a refuel (TB20)...
Time to look at turboprops
Unfortunately they are all pressurised, and cost far too much.