That's why I believe he got a little lost. He may have thought he could find open space/wilderness to deal with some of the evidence still in his possession and with his bloody shoes/clothes, etc. Instead, he turns off toward Blaine and sees that while it's rural-ish, it's not inhabited. He's really paranoid by that point in time and he doesn't know the area. He's been back and forth to Moscow, but I bet he'd never been on that road to Blaine and didn't know where that road was leading - because his phone was off. He turns it back on so that he can find his way back to Pullman.
Out east of Moscow are many places that do qualify as open space, but east of Blaine are a web of local roads, all of them "residential" in the sense that driveways and other smaller roads break off the road that Kohberger took to get into Blaine. Not a place to try and dump evidence. I think he's probably directionally challenged and did not have a clear idea of when he was going to hit the southernmost point of his route leading back to Pullman.
Do we know whether he successfully navigated from the 95 to the 195 on his first trip that Sunday? Or did he go all the way south to Clarkston/the Snake River on that trip. It's possible that he was aiming to get to the Snake on the first trip, got lost, went into adrenalin slump, was exceedingly brain-fogged and just went home.
imo