In case this is of any help in deciding whether to originate from KRT:

1) I flew to the Sudan for wedding three or four years ago. I flew with British Midland via Beirut. This is a dreadful flight in economy, do not do it!
2) I got my visa in London. The bride was the daughter of a Sudanese official so an arangement had been made to expedite the applications of our group but even that took a couple of weeks and the process at the embassy was perhaps best described as whimsical and arbitrary. The embassy kept my passport during this period.
3) Credit cards (other than Diners, the French foreign policy exception!) do not work in the Sudan because of US sanctions (these may have been lifted) and Sudanese pounds do not appear to be available outside the Sudan. As a consequence, all tourists carry stacks of hard currency. Whether the sanctions also affect interbank settlement of Sudan pound transactions, I can't say, but I do wonder how the price of the RTW ticket is actually arrived at....
4) Arriving at KRT airport was, er, opaque. However, I am used to first world airports and their transparency of process. It may be run of the mill for African airports, or even quite good, I cannot tell you. It may also make a lot more sense if you speak Arabic! Again, arrangement had been made for us by the family and we wranglers meet us airside to escort us through the process but it still took a very long time to go through immigration etc.
5) Departing KRT airport was frankly chaotic. The flight list was incorrectly compiled and a couple of our group were in danger of being forbidden boarding but it all got sorted out in the end. Again, the family and the arabic-speaker in our group sorted it all out.
6) We stayed in the KRT "Hilton" - in quotes because, again because of sanctions, the official franchise ran out years ago. I believe it has been rebranded a Sofitel since we stayed. It is a faded seventies Modernist concrete block, with vintage interiors and a nice swimming pool. Wallpaper would love it and it would make a good set for a pre-oil crisis Graham Greene film. It was not cheap!
7) If you get a visa and actually enter the Sudan, you will find a lovely country. The Sudanese are extremely dignified and will leave you to your own devices (not like Egypt!). There is plenty of interest to see - the whirling dervishes, the market at Omdurman, the pyramids at Merope etc. - and the city itself is quite grand, set on the banks of the confluence of the Niles, with islands and boats and boathouses dotted on the shores. We went in December and it was still very hot!
8) I would love to go back. I would also love to use it as an origin for OWE fares but, having flown in and out once, I would rather let somebody else prove to me that it can be done....

Good luck!