I'm the kind of person who packs clothes & personal belongings in 15 minutes for the trip and then spends a couple of hours deciding on which sketchbooks and art materials to pack. But I after many trips to museums, parks and holidays I perfected my traveling set up.
I consider myself to be a light packer. A couple of years ago I traveled for 16 days from London to Brussels - Amsterdam - Riga - Stockholm - Copenhagen - Berlin - Paris - London with a kanken standard sized backpack and on my last trip I was going to Ghent & Amsterdam with my brompton bike and a large kanken. So when choosing art supplies I'm balancing taking things which don't take up too much space but are the materials I enjoy using the most
My art set up now consists of:
Miello Palette: it has a small tray which you can take out and rubber around the edges, so when closed it becomes airtight. I prefer using gouache these days and taking many tubes with me is not an option. I've tried just squeezing the paint into plastic travel sets but gouache dries quickly and then when a lot of walking and traveling is involved it just crumbles and goes all over the place. This palette keeps gouache wet for around one week and a half. So I squeeze pea size of all the colours and I have all my favourite paints with me but they take nearly no space.
Holbein Gouache: an extra tube of white or any other colour I use a lot.
Pentel brush pen: fill in the barell with water and no fluff with finding the jar/water, whip it out of the bag and you are ready to paint.
Nahe plastic pouch: they come in different sizes and shapes and perfect to keep all the art supplies and sketchbook in one place. I have one A5 size to put everything in and then a smaller one for pencils, paints, brushes.