I'm a nevermo, but I married a then TBM girl, so maybe my perspective will be of help to you. He is absolutely, hands-down my favorite human being on the planet. While it's true that Mormons are not one-dimensional and completely predictable, the odds of a successful relationship, given the OP's description of his girlfriend, are slim. Great questions, and a terrific answer, Joanna. My husband is an amazing human being and an international cardiologist. I understand that, and accept that. I cherish my MD husband and Ph. She said we couldn't watch it because the lady who produced the doc was formerly a professor at BYU but has since left the church, so she wouldn't have anything good to say. Marriage is serious business and we are in it together despite our spouses shortcomings.
Somewhere down the road, you will find another girl who will be a much better match for you. It is how she is programmed and it is a fundamental tenant of the religion. A grandpa sense of humor and occasional clever line from an old movie go a long way. It has been very therapeutic to read about other people's experiences. If she expresses interest in converting, be prepared to talk about your beliefs, and help her find ways to learn about and follow them. I chose to get married and move across the state to live with my husband and left my job, family and friends and let me tell you, it's been tremendously difficult to meet new friends in the new town.
I've luckily broken down my GF's defenses about the church a little bit. I met my ex when he was a 2nd year resident and married him when he completed his oncology fellowship. I simply do NOT believe he and I will not be together after we die. I'll definitely talk with her about my concerns, and will be spending time with her family over the upcoming holidays so that will be a good chance to see how they treat me. But he feels I need to stick to one career and be content. If I catch you in the back seat trying to pick her locks, I'm going to send you back to mother in a card board box. There are over promises in the Bible.
Given the fact that doctors, esp surgeons, have a very busy life in US, it seems logical. I know a non-Mormon guy who married a Mormon woman and has kept her beautiful and desirable, by encouraging her religious involvement, even though he avoided Mormonism himself. Mormonism and Non-Mormonism don't link to future lives. I'm not afraid of long distance, nor am I afraid of moving to follow him for med school, residency, fellowship etc. I decided not to answer his calls for some time to think. That is the million dollar question. The idea of a rich doctor is almost antiquated. Best wishes to those struggling with these big, life-altering decisions.