Substitute 1 sweet potato for the carrots if desired.
You can also serve the ingredients in separate bowls and let each person assemble his or her own noodle bowl.
Though this is a traditional Vietnamese dish, I find it extremely difficult to get my hands on a good fish sauce. I've learned that, in a pinch, the soy and wasabi dressing is so much easier to keep on hand, and everyone loves it! I highly recommend each person combine the soy sauce and wasabi individually (sushi-style), as everyone has his/her own version of what proportion of wasabi they enjoy and can tolerate.