Hi grindertek
WELCOME to The Original JWMB.
Please take a look around,
we're a friendly bunch of folks,
and there is a wealth of information to see,
regarding the great man.
You may find these links useful:-
John Wayne:- A Newbies Guide to Duke
Link to Duke's Movies, Co-Stars- Pals Of The Saddle and Movie Locations
Thanks for your post and we do have a dedicated sub forum
Most of information obtainable from books is summarised here.
As far as getting deeper into Duke's geneology,
I think you will find it very difficult!