So, my wife and I ended up deciding to talk to my son about it before my dad showed up just so we can get this done and over with. We've been keeping him pretty well educated about LBGTQ as much as we could, and trying to teach acceptance and tolerance for all things. I think we've succeeded since his reaction was to blink, shrug and say, 'Yeah, okay. If that's what you are. Can I go back to Call of Duty?"
Teenagers.

So I ended up taking my father out to the park so we could talk. We got rained on a little, and he knew I was going to talk to him about something serious, but Mom wouldn't spill the beans. After I told him he paused and said, "Well. That's certainly not what I was expecting..." He asked some questions about trans, and I answered them the best that I could. I could tell that he didn't approve, but not because I was transgender. Rather I think he thought that this was something that suddenly happened to me and that I was making rash decisions based off an impulse, and he didn't want to see me make a major mistake in my life.
And while I understand his concern, I think I finally got across to him that I'd been struggling with this on and off for most of my life, and that the sudden epiphany that I had this January wasn't that I was trans, but rather it was
okay to be trans and still love a woman. It was
okay to want the things I wanted in order to be happy and moreover, it was
achievable. He did comment that when we visited them on the weekend (when I came out to my mom) that I seemed to be happier and more relaxed and engaged with people than I usually am. And I responded, "Well, now you know why."
So. I've now come out to all of my immediate family, and I'm batting a fairly good average. Mom's super excited and wants to do girly things with me. Wife is okay, for the most part. I think she's struggling with it some, but we're trying to be open about our feelings and we both still want to be with each other for now. My son is a teenager, and reacted like a teenager. And my dad is confused, but supportive, for the most part. It could have gone a lot worse. A whole hell of a lot worse.*
Now we're moving onto phase 3: Hormones, and hair removal! And then clothes! And shoes! And wigs! And ohgodIbetterstopwhileI'mahead.
*I could be attacked by angry bees.