Although there is no confirmation from neighbor R. Thompson on what street he saw Mollie "walking nonchalantly," it is in my opinion he had to see her walking east on W. Des Moines Street.
Looking back at
his interview video, if you look closely in the video, he is gesturing with his hands in the direction of W. Des Moines Street.
Furthermore, he is talking on his front porch, and in the background you can see some sort of longboat or wagon on his right shoulder side. If you Google map his location using the street view feature, you can see that same longboat/wagon right off W. Des Moines St.
Near the end of the video, the camera also takes a close-up look on the W. Des Moines St. street sign.
He states "she had to go either north or south." Why? Because at the end of W. Des Moines street, there's no other option.
Why does this matter? Because if Mollie was running east on Pershing Drive, "up the hill" on East 2nd Street, etc. how the heck did she end up walking east on W. Des Moines St., the same street where the bf's house is?
Maybe, just maybe, she made it home after the run then walked towards mom's house where "something" happened.