If I passed as well as you, I would be ecstatic. But, in spite of that, I have absolutely no desire to be stealth, for exactly the reasons you describe. I spent 60 years in one closet. I don't want to transition right into another one. I am so done with closets!
I am out and full-time, and, while I don't advertise the fact that I am trans, I don't try to hide it. If I was passing 100% and someone came up to me and said, "Hey, you're trans aren't you?", I'd say, "Yes, so what?"
I understand that your big worry is the redneck in-laws finding out. I hope I don't offend in suggesting therapy for someone who has finished their transition, but really this is something that you should discuss with a therapist. You have unresolved fears, and you need strategies to deal with them.