Who is my daddy?

Going through boxes can be a difficult task.  I am trying to tackle one or two boxes a week, maybe I can reduce the amount of "stuff" we have accumulated.
We?  Hell, it's the crap I have that causes the problem.
And honestly, sometimes I don't know what to do with it.
Pictures are my main focus this week.
Family History:  My father came to America when he was an infant.  Born in Pozin (Posen) Germany, by the time his mother brought him that part of Germany was in Poland.  So of all the people in my dad's family, he is the only Polish immigrant.
He was born in 1901....so he would be 112 if he were alive today. And he'd be grouchy, because that was his nature.
I don't know him.  Seriously.
He married my mother in 1937 or so.  I actually interviewed my mother a couple of times before she died and have notes.  I should put those in writing and maybe one day I will.
Anyway, she didn't know much about him either.....so his life before 1937 was a blank.  He was 36 when he married.....not exactly someone who did not have life experiences.
So here are my questions.  Look at the pictures and see why I am puzzled.

This could be a picture of my brother Carl, or even me....but it's dad!

My dad (on left, I think) at Camp Grant in Rockford during WW I

Pops in uniform, with a friend or his dad?

He's a doughboy.

Taking aim at the future

With a bunch of guys at Camp Grant....he's in the middle

This is marked Gallup NM 1926

Another Gallup 1926

At some point, he worked at a Glenn Ranch, or Glenn Canyon Ranch.  Note that Mrs. Raney is leaving.

To a good friend, from Cookie

Another reason I am confused.....did his parents own this store?

Man of leisure in California

So, there are some of the mysteries.  What did he do from WW I to when he got married?  I know he was in the service at the very end and was mustered out after training.
And in 1926, how adventurous do you have to be to drive in the west.  Did all of them travel together?  Did they take a train then rent a car, or drive the whole way?  Who are the other people?
Do I have half brothers and / or sisters running around in California?  Inquiring minds want to know.
What I realize is the importance of labeling pictures.  And talking to your parents.  You may find a whole lot that you didn't know.
I think it's kind of neat that I have a direct connection to WW I..... even if he was a short term doughboy who never saw action against his homeland.