The trailer does not set up Midworld
Within very short time in the books we know Midworld is not a new, well functioning place. Its inhospitable, its... moved on.
From what we see, there is no waystation. To me, that was one of the first things that established the moved on nature of Midworld. Part of that was by establishing that there was once a civilization that was extremely technically advanced and is, other than a few wearing down or completely broken relics, long gone.
Roland is constantly shown in clothes that are in good shape, rather than weathered, faded, and old. Gilead is dead, the world has moved on, Midworld is inhospitable, and Roland has been chasing Martin for decades. There aren't places he can just pop in and buy clothes off the shelf. He either makes, repairs, or finds them.
I'm hoping they have taken the time to establish Midworld as having moved on, if, indeed, it has moved on.
[removed a two sentence comment at the end of this post about a hat because its detracting from the post]