They will probably all be neutrals, but this is one of the fun creative things - coming up with a color scheme that works this way, with colors you wouldn't expect to be neutrals. Each piece should be in plain solid colors to maximize flexibility. Bring scarves and belts to vary the looks of your garments. Use fabrics that don't wrinkle and which dry quickly. For me, this means a high quality interlock knit.
Jeans are bulky and take a long time to dry.
These garments should be non-binding because you'll be spending hours crammed into a very tiny space. Hang on a travel clothesline or inflatable hanger as appropriate. This will take you about five minutes. I'll be showing two tables, one for a more casual tourist-type travel situation, and the other for a business trip. A vest and a cardigan jacket fill it out.