You'll be in perfect position for a drive-by of a good portion of the Nebraska Sand Hills. As you head east, you'll be in the Platte River Valley and you'll start noticing large hummocky grass covered sand hills in the distance on each side of I-80. That's all you'll see by staying on I-80 to Grand Island. On your return from St. Edward, head west on NE state highways to NE-2 at Broken Bow and run NE-2, affectionately named the Sand Hills Scenic Journey, to Hyannis, then drop south to Ogallala to pick up I-80 just east of the I-76 split which takes you down to Denver. Or, stay on NE-2 all the way to the western edge of the Sand Hills just east of Alliance, stop and visit Carhenge, the take US 385 south towards Cheyenne to pick up I-80 and cross the Great Divide Basin desert on the return trip.
NE-2 is a great drive. All 2 lane, but wide with broad sweeping curves and mostly 65 mph speed limits. The Sand Hills tower 300' to 400' over the roadway in places and there are a number of cool little railroad towns, starting with Broken Bow.
Foy