I have a K-01 and a K-r. My opinion is that the K-01 has better image quality and the focus peaking can be a very useful feature. With the new firmware, its AF has been improved, as well. The K-r, however, has the optical viewfinder, so you don't have to look at the LCD screen to take photos, and it has PD AF. Phase detect AF is generally faster, especially when the target is moving or if you have a slow lens.
The K-r is pretty tiny, but the K-01 is smaller and can fit into bags better, with its blocky shape. Its a hard choice to make, for sure.
That lens will fit your camera, as will any other Pentax K lens. You can look at the lens reviews on this website for more information, pretty much all lenses are listed and reviewed, including sample photos.
The only thing I would suggest to you for motorcycle use is to invest in a good, soft camera bag, because the vibrations of a motorcycle can potentially rattle the camera. The K-01, being mirrorless, might actually be better in that regard. Fewer mechanical pieces.
The K-30 actually has OVF and the same sensor as K-01, but is also WR, which can be great when you drive in the rain or something I dunno
But hey, the K-r has all the features you need and its not too expensive, get it with warranty and have fun. There is a thing known on these forums as buying addiction, when a person always wants the next better camera or lens, even though they don't even need all of that
I've had my K-r for a long while now and its been great.