How many lenses do you intend to take?
I recently spent two months in Europe and I travelled light. I had my DA18-250mm, Voigtlander Nokton 58mm f1.4 and DA15 mm Ltd.
My selection was based upon a simple reasoning and past experience:
-a walk around lens (DA18-135mm, DA18-250mm)
-a fast prime (VL58mm f1.4, DA*55mm f1.4, FA50mm f1.4, FA31mm f1.8...)
-a wide angle lens (DA15mm...)
I tried both DA18-135mm and DA18-250mm. I like the longer reach of the DA18-250mm and it would be my recommendation.
For a fast prime, you may prefer MF or AF. I found that MF is more accurate and very low light.
For a wide angle, the DA15mm Ltd is really nice.
As I travel light, the DA18-250mm is typically mounted on the K-3. I have the DA15mm and VL58mm in my jacket pockets (one on each side). When I put a prime on the camera, the walk-around lend goes to my small camera back.
I placed a few examples at:
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/246655-primes-paris.html
Hope that the comment will help.