The southern Sinai has produced a small but interesting literature. Three books between them give a good sense of the place beyond the resort fence:
Sinai: The Great and Terrible Wilderness by Burton Bernstein. A 1979 New Yorker piece expanded into a book, tracing the journey of the Israelites — and of the author — across the peninsula. Dated in its politics but extremely readable on the landscape and the people.
The Bedouin of Mount Sinai by Emanuel Marx. An anthropologist's study of the Jebeliya tribe who have lived in the high mountains around St. Catherine's monastery for fifteen hundred years. Clear-eyed about how Bedouin life has changed under successive occupations and the arrival of tourism.
Sinai: A Physical Geography by Ben-Avraham et al. Drier than the others, but indispensable for understanding why the landscape looks the way it does — the volcanism, the granite, the rifting that opened the Red Sea. Worth dipping into before a trip into the interior.
Beyond the Reef: The Underwater World of the Red Sea by Bernhard Edmaier. A coffee-table volume of aerial and underwater photography that captures the strange, vivid quality of the Red Sea biome better than most books on the subject. Good preparation for the snorkelling.