Have just returned from fantastic trip which was also our honeymoon. Have a few tips that might come in handy for potential travellers :
1. It is still freezing in March/April on top of Mount Sinai before sunrise. We took our sleeping bags up and waited an hour for the sunrise. After a long sweaty walk you cool down real quick. We wished for balaclavas on top - if you have one take it.
2. Feluccas - it is quite often too difficult to sail at all on these depending on no wind or too much wind. Be prepared - you may be marooned at many stages over the trip and the boats will just pull over for safety. We didn't sail for most of the 1st day of our trip and we were bussed in to the last temple at Edfu due to being unable to get there on the felucca in time. Don't get frustrated - just be aware that it can happen. It can also be chillier than you would think at night on these at the moment, so bring something comfy and warm to wear at night in your bag.
3. Egyptian Obelisk red wine is great - try some. It makes a nice change from the ubiquitous home brew Stella.
4.Pound Sterling - Scottish pound sterling bank notes are not legal tender anywhere in Egypt, even in main banks and can't be exchanged. Bank of England