A few people have asked me about doing art while travelling and which materials to use while sketching on the go. Obviously it depends on what kind of art you do, but here are some things I like to bring with me:
1. Watercolour pencils: you can use them as normal colour pencils or add water for painting, they're less messy than just carrying tubs of watercolour paint. I use a Faber-Castell's Albretch Dürer set with 12 colours (which is plenty, because you can work on layers and get lots of different shades and hues). I'll usually bring a knife along to sharpen them too.
2. Liquid pencil: I only just started using it and I LOVE it, it works like watercolour but when it dries it has the same finish as a pencil. It's great for shading pencil sketches quickly on the go. It comes in a tube and it has a paste like consistency, you can add water to it just like with watercolour paint.
3. Refillable water brushes: they're empty brushes you can fill with water! Super handy so you don't have to have a tub of water for using that liquid pencil and watercolour pencils
4. Pigment liners: good for sketching quickly too, nice intense dark strokes.
5. Ballpoint pens: I love drawing with ballpoint pens when I have more time because you can get beautiful soft fades and hard lines too.
6. Lead pencil: self explanatory and better than a normal pencil because you don't have to sharpen it.
7. Sketchbooks: I like having two, one for quick pencil sketches, taking notes, journaling and collecting tickets and other things during the trip. The other for more elaborate colour drawings, with nice thick watercolour paper.
Hope that helps you have some ideas to build your own kit :)