Wash chicken pieces, remove any excess fat. 

Rub chicken with olive oil, season with salt and pepper .Lay in single layer on sheet pan with sides and roast at 375 degrees in oven for 1 hour. Now follow the remaining directions for shorter method.

In large stock pot add olive oil, onion, chicken, salt and pepper. Brown onion and chicken pieces together until onion is tender. About 10 minutes. 

Add 64 ounces chicken broth and water to large stock pot. Cover, bring to boil, simmer at soft boil for 1 hour or until chicken is tender.

Remove chicken from pot and set aside to cool slightly. When cool enough to handle, Dice chicken into bite size pieces.  If using chicken with skin or bones, now is the time to remove those.

If you used chicken with skin and bones you may need or want to skim some excess chicken fat off the top of the soup now.  Use a large spoon and just skim the melted fat off the top of the broth.  If you used skinless/boneless chicken, you will not need to do this step.

Add carrots and celery to stock pot. If using mushrooms add these now as well. Cover and simmer until carrots and celery are tender. If there is not enough stock, now add the remaining 32 ounces chicken broth.  You could also add water if you don't have extra chicken broth.  If using water, I would add an additional 1/2 tsp of salt.

While veggies are cooking, cook noodles according to directions in separate pot.  Drain.  If timing works out and the veggies are now done, you can drain and add directly to the stock pot.

Add diced chicken to stock pot, and any optional veggies if you are using them. Simmer for 5 minutes.  Taste to see if additional salt or pepper is needed. Serve with a great crusty bread or crackers.