Is the sightseeing private or a group?+
A group. The operator states it plainly: all sightseeing from the cruise runs as a shared small group of roughly fifteen people. Your airport transfers are by private air-conditioned vehicle, but the temple visits are shared with other passengers from the boat.
Are domestic flights included?+
No. Domestic flights are excluded on this trip, along with international ones. You need to get yourself to Aswan for day one and home from Luxor on day four, and both are separate bookings. You are met at Aswan airport and dropped at Luxor airport.
Which direction does it sail?+
Aswan to Luxor — northbound, with the current. It is the shorter and usually the cheaper of the two directions. It also front-loads the quiet end of the river: you start at Philae and finish with Karnak on the morning you fly out.
Which meals are included?+
All of them on board. Three nights of full board, starting with lunch on the day you embark and ending with breakfast on the day you disembark. Drinks on board are paid extra. The boats publish no drinks price list, so ask for one before you board. Bottled water in the vehicle during transfers is covered.
What is not included?+
International and domestic flights, your Egypt entry visa, extra meals and beverages, optional tours, tipping, and additional entry tickets. Tutankhamun's tomb in the Valley of the Kings is the usual example of the last one: it is a separate ticket bought at the site.
How much walking is there?+
A fair amount on three of the four days, in the open and mostly on sand or uneven stone. The Valley of the Kings means walking between tomb entrances and down into them, and Karnak is a large site. The boat is your base every evening, which makes it easier going than a land trip of the same length.
How much should I budget for tipping?+
Tipping is excluded from the price and it is expected. Allow US$10–15 per person per day for the guide and about US$5 per person per day for the driver. On the boat there is a crew box at US$5–10 per person per night, collected once at the end and split between the cabin stewards, waiters and deck crew.