Originally posted by clackers I'm sure you can travel the world with just that K-3 and Sigma 17-50 and take great pictures, Deckroid.
Tim B travelled right through South east Asia for months with just one body and the 16-85 from memory. He discussed in an earlier thread and provided his Flickr account to show what's possible:
Best of Asia trip | Flickr
So I agree with Clackers and have Tim's evidence, but I would never do it personally - I would always take two zooms and a couple of small primes. The kit I would take from my collection (today's thinking only, not tomorrow's), is the two current WR light zooms (18-135mm and 55-300PLM), the DA21mm and DA70mm). I have a DAL50-200, but the 55-300 is miles ahead in image quality and focus as well as reach, so I have never used the DAL since I bought the 55-300mm. The WR zooms would be more comforting in the deserts, and in the dank outdoors of Scotland.
My superzoom is a Sigma 18-250mm HSM, and I rarely use it because or the weight and minor compromises in image quality. I would not rely on it for a once-in-a-lifetime trip.
I like the Limited primes for travel as they are tiny (pocket or handbag-size tiny) and work well inside in low light but your Sigma 17-50 is also a star for that (admittedly much heavier though for carrying around all day).
You have the 17-50 so that plus the 55-300mm would be enough zooms as per BigMackCam's suggestion and would give great quality images,. You could leave without any primes (then buy if necessary as you go) or slip in either a fifty or a macro if you have one.
If you have, as your profile says, "many many filters" then maybe you have a closeup set that will attach to your fifty to make it a macro? I have a really good Canon macro52mm aux-lens with a 49-52 stepping ring that will work on any of my Limiteds or fast 50s to turn a sub-200g lens into a fast macro.
Enjoy the trip and let us know how it goes photographically and socially.