You already have a lot of zoom covering focal lengths between 16 and 200 mm. Would you consider some prime lenses? Pentax has a lot to offer and prime lenses can offer great IA..
For landscapes, I like to use the DA15mm and the FA31mm f1.8 Ltd. The DA15 is a wide angle lens and I enjoy it. The FA31mm is fabulous, a reference lens. Both lenses will work very nicely with your cameras. I use them with my K-7 and K-01 with great success. I think that these two lenses would complement nicely your lineup and be useful for your cruise.
I recently discussed a trip during which I took a lot of landscape shots and I used my FA31mm and VL58mm:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/209251-fa31mm-...mm-f1-4-a.html.
Hope that the comment may help.