I'm going out on a limb here to ask if the OP has asked the picky steak eater what she means by a good old American steak. As we all know, taste is highly subjective, and takes into play past experiences with culture, family experiences, smell, how food looks, and tastes, textures, and memories of loved ones with whom food was shared. It is nearly impossible to make a specific kind of food for someone without them giving you a place to start. She needs to say how she likes it done, whether it's blue, to burnt. She needs to let you know if she likes it seasoned, or just likes the beef flavor to shine through. She has to tell you if what she was used to was corn fed, or grass fed, if she knows.
One can not know what another person likes without one of three situations;
1. She tells you in detail what makes a steak great to her
2. You've had the chance to observe her eating steaks of different types, and witnessed her response to them.
3. You've eaten what is to her, the perfect steak.
After that, it's simply conjecture
As an example, I once met a lady who stated that she made the most wonderful steaks. I and my wife were invited to dinner, and she cooked up her version of the most wonderful steaks. I watched her prepare the steak. She took perfectly good strip steak, seasoned it with salt, then liberally sprinkled baking soda over one side. Then she pierced it all over, strating that the baking powder would tenderize the meat. She did the same to the ohter side. Then, she picked up the steaks and put them on a hibachi, over hot charcoal. These were the worst steaks I had ever eaten, for my tastes. Yet, the lady who prepared them thought they were amazingly flavorful and tender.
That's an example of how wildly different tastes can be.
If you have no background, you have very little chance at success.
Oh, one other idea for you; do you know her family, i.e. her brother/sister/parents. If so, you could email them the same question about her beef eating preferences.
Seeeeeeya; Chief Longwind of the North