i am currently working a similar itinerary . here is some of what i have found, hope it will help.

1. the egypt domestic flights should be quite cheap. but it is best to purchase tickets through a travel agent there instead of the egypt air website. the prices could be as much as 75% less.

2. there are sleeper trains that run from cairo - lux - aswan. if you do an overnight, the time in transit is moot. they look kinda nice and do get good reviews. see www.sleepingtrains.com

3. Aswan. Although I have not finished my researched on this city. most tours to abu simbel leave at 3am for overland tours. air egypt has a flight and tour as well (not sure what time it leaves), if you select the former, you cannot sync with the overnight train.

IMO if you have to see abu simbel, and i cannot imagine not seeing this personally, you almost have to dedicate 6 days to the upper nile region. but, it is also my understanding that the maximum time you have at the site is 2 hours, due to crazy govt. regulations, this might be a deal braker for some.

4. Aswan. We just found this company via the net and i have my agent in cairo checking it out, but looks like a nice ride if you plan on doing a short nile falucca curise. www.gloryofnubia.com