About 5 years ago I was anticipating a trip to Germany to visit my daughter. I wanted a kit that would cover what I thought I used most, and be as compact as possible. I already had a Yashica FX103, a Yashica FX3 (for battery-less backup), and a Contax 50mm f/1.4. I had the dedicated flash. I also had a Welta Weltax for MF. That was the start of my kit.
I decided on three zoom lenses. For a telephoto, I had a Yashica 75-150mm f/4. Light, covers a useful amount of focal lengths, and since I anticipated it would usually be used in daylight, f/4 is fine. I believe 75-150 is a good telephoto range. My type of photography, I don't need to reach out to the moon as a rule. I seldom use my 300mm, 500mm, or long zooms, even the 80-200mm zooms. YMMV. In the unlikely event I wanted to reach out further, I had a 2X extender. Yashica lenses are respectable lenses to use. I have the feeling the old M42 lenses might be better, but the bayonet versions are still good.
For in between, a Vivitar 28-70mm macro, f/3.5-4.8. Again, useful focal lengths, macro, a little slow, but not so much worse than the others. This is a fairly compact lens for what it does. I don't use macro much on outings, but it was there if I wanted. 28-70mm is a very useful focal length range. Wide at 28mm, and mild telephoto at 70mm. 70mm is a good enough portrait focal length. Vivitar may not be the best lens line out there these days, but it isn't a holga either.
Lastly, a Samyang 18-28mm f/4. That was the most desired focal length to cover for me, but a Samyang was questionable in my mind. 18-28mm lets you get a lot of village scenes of narrow streets and/or markets. I have never been to europe, much less Germany, but I anticipated wanting a lot of photos like that. The Samyang turned out to be much better than you might expect. It is a little large, and makes some noise when shaken. But it is surprisingly sharp.
As I mentioned, I had the Contax 50 f/1.4 also. For really low light, or if the sharpest lens I had was important, it was there. The dedicated flash would take guesswork out of flash work when wanted, with the otf it utilizes. I took my Gossen Luna Pro since it is reasonably small and very accurate if everything else failed, or to use with the Welta Weltax I took along for MF shots. All that fit in a small bag, but was still very accessable. I was surprised.
I never made the trip, but it has remained a useful kit nonetheless. Two good cameras that are somewhat compact. Focal lengths from 18mm to 150mm. If I want MF, the Welta Weltax (a folder) delivers good MF photos. Sorry for the long post, but it was my solution, and I thought it useful to explain my choices.
