Where are you going and what will you be doing? And what does your skin NEED on a daily basis? Eg, if you're not prone to acne except on rare occasion, why bother packing it?
I never had a real skin care regime until this year, but even so, I would ALWAYS pack spf 45, a bottle of moisturizer, and hair conditioner. I'm an outdoor enthusiast ... my occupation and the activities I enjoy tend to be near salt water, hence those 3 items were always with me. I never cared about what moisturizer then, just that it was a nice one and felt good. While I don't have dry skin (it's normal), salt air and water can wreak havoc on skin.
Now, since my enlightenment on real skin care this year, I pack toner, a moisturizer with vit C and E, another moisturizer that is creamy and contains mango butter and rosehip oil, and facial cleanser with 2% salicylic acid ... and sunblock.
As I learn and experiment more, I'm sure the individual products will change, but there will always be a low-level AHA/BHA in toner or cleanser, one or two moisturizers with the ingredients in them which I feel are beneficial to "my" skin and "my" skin care goals. Oh, and a high SPF sunblock of course.
Have fun wherever you're going!
Kathy