My first advice would be that you slap whoever gave you this assignment upside the head. If you're going anytime soon, take your longjohns. In warm weather, Nebraska is covered with corn and cows. Right now, probably just cows. However, the people are nice, although you probably should not start a discussion of U of Nebraska football these days. One feature of rural plains and prairie states is the considerable absence of air pollution, except near feedlots, so that landscape photos often show deep blue sky and very little atmospheric perspective.
When I taught in South Dakota I traveled through this area a lot back to Utah. I've only seen it in passing, and have never stopped for any number of days, but I do have my impressions of the area.
In all the route between Brookings, SD, and Provo, UT, US83 between the South Dakota border and Thedford, NE, were always the prettiest and most interesting, no matter what time of year.
I would loved to have spent more time in the Sand Hills, shooting the wondefully remote, cow-pathed and green hills in the Spring. In the Winter they were all together different, more forbidding, but the way the cloud-diffused sunset played on the hills was glorious.
I also wished I could have taken a bit more time with the two bridges just North of valentine. They crossed quite a gorge there, and one bridge gave an excellent view of the other.
Here's one of the very few shots I took in the area: Dead Link Removed very early in my photographic training.
I own a cabin up right near valentine, and the area is beautiful. There's lots of opportunities for taking photos of people in there own situation, like ranchers, or old retired people sittin on the porch watching deer.
I'm guessing that you've already left and came back, so i hope you had a good trip.