What Lens for Luggability?

I would take 2.

I'd take the 12-50mm because it covers a wide range of focal lengths, and, while not perfect, captures pretty good images. It can also be used in bad weather, if you have a weather proof camera.

I'd also take the Panasonic 20mm f1.7 because it's tiny and sharp as hell. I'd use that for anything where you do want really sharp images, or in low light. It's tiny so it can go in a shirt pocket.

So, general photos, castles, city streets, etc – 12-50.

Detail photos - artwork, city skylines, landscapes, etc – 20mm.