If you have no contacts (read rich millionaire friends) or no money (you are a CFI, so you're poor), the best way is to volunteer at your local flying musueum. I know of numerous examples of individuals who started volunteering at musuems when they were in their teens or 20's and now in their 30's and 40's are flying major warbirds, including the ones you talk about. The thing with flying museums, is that they want some kind of assurance that you are serious, committed and willing to spend the time it takes to fulfilling the museum's goals and mission statement. If you can do that, it will open many doors and contacts to enable you to fly the big iron. Nobody, and I mean nobody will let you fly their warbirds unless you have the experience and qualifications to do so. Even if they were stupid enough to allow it, the insurance company would not allow it. So, in order to do that, you must get lots and lots of taildragger time.
You must start out slow and work your way up. For example at the Planes of Fame museum at Chino, the volunteers usually start out on something light and slow, like the L-5 or Stearman, then progress to the T-6 and then the more forgiving big iron, like the SBD, then Corsair and Mustang.
If you do decide to go the volunteer route at a museum, realize that it could be at least 10 years before you get the opportunity to fly the big birds. When flying Museums check out pilots to fly their big warbirds, they only give that priviledge to volunteers who are qualified and have proven their dedication to the Museum's needs. Remember, everybody starts out sweeping floors at the hangar. It is a long road to fly the planes, but it can be yours if you have the desire.
Just my two cents from what I've seen at Museums and heard from my friends in aviation.
Good luck!
