I would start here. Every base that you are near has a Tricare Advocate to help answer all your questions. Most find that TC Std is more than adequate with most other retiree care. You can try here to begin with:
http://www.tricare.mil/bcacdcao/
I would call the base near you and personally talk to the Tricare advocate. They know all the answers and have a vested interest to help you get all that you are authorized and have earned.
JV