I'm looking at 3 day packs. Should I get one in multicam to match my OCPs, or tan to be a more discreet when traveling?

Solid tan is more likely to be authorized

If you're sticking to these options then go with cammo as tan is unauthorized in uniform. Personally, I bought a black computer backpack with no logos from the PX. Still within regs but much more discreet when traveling in civvies.

tan , cant go wrong with it

Was so much simpler when you couldn't wear utilities, fatigues when traveling. Just a little black AWOL bag is what you carried.

Tan

I agree with everyone above it doesn't really matter it all comes down to what you want they are all authorized and either way standout in an airport.