While traveling, how often do you shoot 24mm to 28mm, and 80mm to 120mm, full frame? That's about what you'll miss using the 18-55 instead of your 24-120?
I have a 14, 18-55, 23, and 90. Together these more than cover my needs while traveling.
If you want to select two lenses at most, small and light, I'd take the 18-55 and select the second lens based on destination and anticipated subjects.
I have a D800 and had a 24-120/4. It was my full frame travel lens, before I sold it. After I picked up the 18-55 (first on my X-E1 and now on my X-T1), the 24-120/4 just sat on the shelf gathering dust.