Stabilize your BGE at 375 degrees. Use a raised grid. I use three pieces of firebrick on edge to place a second grid over the first. (See the recipe for Spatchcock Chicken for a photo.) Get the orange wood smoking before you place the breasts on the grid. Spray or brush the breast with a little olive oil and place them on the grid. Cook for 35 minutes, turning 2 or 3 times during the cook.
When the chicken breasts are done cooking, cook the fettuccine noodles according to the package instructions. While the noodles are cooking, you can get the other ingredients ready. Prepare the peas according to the package instructions, i.e., toss them in the microwave for 3-4 minutes. Saute the mushrooms in olive oil. Add a splash of cooking sherry if you like. Cook the mushrooms just enough to soften them up and allow them to absorb some of the sherry. Drain the mushrooms when they are done cooking. Dice the chicken breasts into lovely sized chunks of meat.
When the noodles are done, you should have waiting: the hot peas, hot mushrooms, and hot chicken meat. Drain the pasta in a colander. Return the noodles to the pot you cooked them in. Add the chicken, peas, mushrooms and Alfredo sauce. Toss until the ingredients are evenly coated and distributed.
Serve immediately with cracked black pepper, grated romano or parmesan, and foccacia bread. (Buitoni also has a couple of nice foccacia bread mixes.)