I can answer the question myself now.
The biggest news is that you can count on the park having food in their basic restaurant, so it's not required to bring your own (wish I had know this myself before I got there). You can confirm this by phoning the park director's wife Josephine, who runs the restaurant: 0782146535. Or calling Patrick, the UWA staff in charge of tourism at the hostel: 0779086239
I ended up doing a big loop though the north, approaching Kidepo from Gulu, then heading south from there to Mbale. Doing things in that direction ensured that i wouldn't need to be traveling at night, which seemed prudent. From Gulu to Kitgum i easily caught a three hour share taxi in the morning, arriving at about 11Am. There is indeed a new UWA office in Kitgum (sorry, I forgot to get the phone number) staffed by Joffrey, who was very helpful. From him I learned that there was a UWA vehicle coming through later in the day that could give me a lift straight to the hostel in the park. That leg took about four hours, which is probably shorter than you should expect, because we were really moving (the park director was in the cab of the truck). You should also give yourself time if you're going to have to switch vehicles at the park entrance. Joffrey can arrange a park vehicle to meet you there, or you can take your chances that you can find transport in Karenga, which could be cheaper (the park vehicle would cost 3000 SH for the 22 kilometers in the park itself, at least that's what the charged me for the ride out).
There was one truck going from Karenga to Kabaang the day I was leaving, so that worked out easily for me. It wasn't clear if there was lodging in Karenga if I needed it, I didn't see it, but I was told very basic rooms were available. THere were no trucks leaving from kaabang that day or the next, but I eneded up not minding, they were two of the most enjoyable days of my whole trip. People were extremely friendly, and the lodging (in the blue building at the southern edge of town, forgot the name) was basic, but comfortable. There is one restaurant in town that didn't scare me, the Riverview (?) up past the junction. Very friendly and clean. I had a great time just sipping beers with locals at some of the tiny roadside pubs.
The next day I was able to hitch a ride in dilapidated truck to Kotido, another freindly beer drinking town, and from there it's easy to catch a early morning bus to any point south. I stayed in a basic hotel listed int the LP (again, can't remember the name, and I gave my book away), but the locals recommended "the Cave" which they said was the same price, and better.
Hope that helps anybody heading up to Kidepo, which i recommend, as much for the journey itself as the park, both are great.