That is weird how they couldn’t figure out how he got to and from work everyday. Even if he walked the two miles everyday I’d imagine he’d be seen by multiple people also on their way to work at the same time. I doubt he took the bus because as you stated nobody ever came forward saying they seen him. I take the bus myself into the city for work and I see the same people every single day, morning and night. At least one of them would have come foward and said they rode with him if he was taking a bus.
I’ve always thought that Frazier had more involvement than he let on and believe he was Oswald’s ride to work everyday. The police trying to make him confess to being involved in the assassination would only make him distance himself from Oswald as much as possible. I don’t blame him for staying quiet all these years but do hope he comes foward if he knows more before it’s too late.