To begin with my thoughts on the two songs:
Locomotive: Definitely a great, great banger. Reminds me of her old work. I can hear Kerosene, Down, Getting Ready (which remains one of my favourite Miranda tracks) and Crazy Ex-Girlfriend in this track. I like the nod given to the imagery in her previous album where she says, "He gives me wings". I can't see radio playing this but I have a feeling this will become a fan-favourite.
It All Comes Out in the Wash: Personally, I absolutely love songs like this. An infectious melody, a tongue-in-cheek lyric and having a groove that makes me want to move. What I find relevant to bring up here is something that Faraway has already touched upon: I think an artist should not constantly try to best themselves. It's impossible to replicate what one has made before. This was a conversation I had with my brother a couple of months ago when he thought Taylor Swift's "ME!" was not up to par with her previous work; and I said the same to him, that if she tries to up her game every time, she will start making music that is perhaps over-calculated, does not personally resonate with the artist too much or just start lacking heart. That is the same with Miranda too. TWOTW was an absolute body of genius and if she tries making music that is equally as good, she will lose personal connection with her songs. So if IACOITW is a song that Miranda really enjoys singing and listening to, and something she thinks represents her current mood the best, I support that decision. I think we sometimes tend to be a little too hard on artists for not producing what we think is "quality" work. But personally speaking, I like to support their decisions and trust the sound they want to go with (unless it's something completely off the mark, like The Band Perry trying to revamp themselves). So with that being said, I'm not going to compare this record with previous ones in terms of whether is matches the bar or sets it higher. I'll enjoy in its individual standing.
(I do want to clarify that this post is not meant to be defensive at all. It might sound like that but tone and intention are often lost in writing. So I don't mean to attack anyone's opinions. Just trying to give an objective perspective of what I think of the new music.)
As far as "Too Pretty for Prison" goes, it's a duet with Maren Morris. Maren posted an excerpt from an interview Miranda gave where she confirmed that the song is a duet (although I have been unable to locate which interview it's from). Maren and Miranda seem to have gotten a lot closer in recent times (the first time I saw them openly admire each other was at the CMT Artists of the Year showcase). They have performed together and are going to tour together too. So I'm really looking forward to this song.