You could always ask for an ultrasound to verify a miscarriage before you take your trip. You could still miscarry like a normal period; it will probably contain more clots. There's also the chance of heavy bleeding that needs immediate medical attention.
I've had a number of m/cs myself. Most of them resolved on their own, but I had to quickly get myself to the doctor's office for one with heavy bleeding and another one I needed the D&C because it never expelled itself. I'd be nervous about the chance for the heavy bleeding if you're going on a trip. If you are flying, I'd postpone it if you start having cramping. The heavy bleeding was a bit scary but quickly remedied once the doctor did his thing.
I don't recommend the D&C, but it might be your best choice at this point with the trip so close(ultrasound first, though). I prefer the meds over the D&C, but not sure if you'll have the time to make sure it works.
I'm so sorry for your losses.