I believe Capture One Pro would be the best RAW converter / image management software for the K-1.
Phase One's software is used by professionals all over the world and not only provides better colours for Pentax cameras out of the box, but also has a much more advanced colour editor that is a lot more flexible and can even increase the uniformity of skin tones.
The "structure" control (in addition to the standard "clarity" control), the flexibility of the user interface, the B&W conversion options, etc. -- I could go on and on -- make Capture One Pro a better choice than Lightroom, IMHO.
Phase One seems sympathetic to supporting the K-1 but said that all their feature additions are request driven. So if you think Capture One may be for you and your K-1, please
let Phase One's support know. They are really good in listening, even if you are not a customer yet. They have endured a number of enquires from me before I acquired a license and have always provided helpful responses.
While you are at it: Why not let them know that you'd really like support for Pixel-Shift Resolution?
FWIW, I have been using Lightroom for years, really enjoyed it (save some really annoying bugs that were never addressed in uncountable updates), but got tired of trying to coax natural colours out of my K-5 II using Lightroom and wasn't happy with their product philosophy (everything going mobile, cloud, and subscription-based).
I'm rather happy with Capture One Pro now and cannot wait to get as proficient with my keyboard shortcuts (which are customisable(!), in contrast to Lightroom) as I am with Lightroom's.
Just a quick video, demonstrating the out-of-the box performance which should not be construed as a comparison of what the best possible output is after tweaking, but should also not be underrated as time saved in post-production can be spent in lots of useful ways.