First, make the dressing. Combine all the dressing ingredients in a food processor, and blend until smooth and creamy. You can add a little more milk to make it thinner if you wish.
Cook the pasta according to package directions, then drain well and pour into a large bowl. Toss with the dressing.
Cook the bacon to desired crispiness, drain on a paper towel, and add to the pasta. Mix in the lettuce, tomato, and avocado. Add more salt and pepper to taste if needed, and enjoy!
*NOTE* If making the pasta salad ahead of time or saving leftovers, mix in the lettuce right before serving or it will wilt and become soggy.