My standard carry around set up is the Tamron 17-50 + the Pentax 55-300. A good combination IMO. When used well, the 55-300 can produce good results, and is not particularly heavy or bulky, and holds F4 to about 200mm focal length. Extremely well behaved in regard to purple/green fringing. Holds sharpness well to around 250mm but is still pretty good at 300mm. The 17-50 is a sharp lens and the F2.8 is very useful when visiting museums/historical buildings when travelling.
The 55-300 at 300mm and F8 with a fast moving subject:
And yes, the pciture is the right way up!