I confess, I've never managed to come up with ideal kits for different purposes, and I always struggle when the time comes to choose what I'm taking with me
So far as my Pentax (or Pentax-compatible) kit is concerned:
If I'm just looking to cover basic shooting needs and want a simple kit, I'll usually take either my K-3 or Samsung GX-10 depending on my mood, spare battery, and Tamron 28-75mm f/2.8.
At the other end of the scale, if I'm going away for a few days or more and want to have the majority of possibilities covered, I'll take my K-3 with battery grip, charger, spare batteries and SDHC cards, Sigma 17-50 f/2.8, DA*60-250 f/4, HD DA1.4x rear converter, DFA100 f/2.8 WR and possibly the HD DA15 f/4... but so long as I have the 17-50 and 60-250 with me, I might pick different primes depending on how I'm feeling. I'll also take my Metz 52 AF-1 flash, Vello hot-shoe cable and sensor cleaning supplies (usually just a rocket blower and gel stick). Depending on the situation, I might also take my tripod and IR remote. Usually, I carry a compact camera with me too (often the FujiFilm XF-1), or sometimes the Q7 and one or two lenses - either for backup if my main camera dies, or for days where I just don't want to carry a bulky camera and lens(es) around
For situations in between those two extremes, it gets murky... I might still take the Tamron 28-75 f/2.8 but augment it with a favourite prime or two, or the HD DA55-300 WR. Or I might just take three primes to cover wide, normal and short tele. Frankly, there are so many possible combinations, and I almost never get it absolutely right - though I rarely find myself without sufficient coverage; just sometimes it turns out that I took too much with me or didn't take quite the most optimal pieces (both common occurrences!).