Google maps (so take with a grain of salt) says...
All example times start at Columbus and end at the I-80 exit for Grand Island (Tom Osborn Expressway)
Hwy 81 south out of Columbus is 1 hour 30 minutes
Hwy 14 south of Central City is 1 hour 23 minutes
FarmerRick's route on the east side of Grand Island is 1 hour 19 minutes
Looks like FarmerRick wins the prize.
Fly