I only have a K-3, so that would be my favorite body. I sometimes dream of the built in GPS on the K-3 II, but it wouldn't fit my Yongnuo flashes with the larger hump.
My favorite lens is definitely the 18-135 WR. It's fast, mostly silent, and covers almost all the range I need. I pick it over my other primes / long zooms almost all the time since it just works so well. My only gripe is that it's only weather
resistant, and zooming will still pull humidity into the lens so it can fog up if you go from warm to cold (like going from the beach into an air conditioned hotel). I wouldn't trust the WR for continuous use in the rain, but at least I know that a sudden downpour won't destroy my camera before I can get indoors.
For playing around for fun I like my Pentax-A 35-105 f/3.5. It performs great in low light, but I have trouble manually focusing with the K-3 stock focusing screen in the dark (when I really want it!). When I have time and I can double check focus in live view or take multiple shots I use this lens for super clear pictures since it really is like a stack of primes, but if I don't have time to futz around or there's plenty of light I just end up using my 18-135 instead.
Things might change slightly this Christmas if Santa's elves can reverse engineer a 17-50 f/2.8 and forge a copy for me
. I will still probably bring my 18-135 for travel though, since the WR is a nice reassurance if the forecast even hints at rain.