I think you'll find that a road bike is a lot more intuitive than it might otherwise seem. It's easy to get the hang of it. As for transitioning from the more upright position of a MTB and the more horizontal position of a road bike, assuming the road bike you choose otherwise fits you, I think you'll also find it to be pretty comfortable. It may take some time for your neck muscles to adjust, but if you gradually increase your mileage, you should be fine. I, personally, would start with the bars level so that there's no "kink" in your wrist. You ideally want your hands and wrists to be in a fairly neutral position, almost like you're shaking hands with someone. By tipping them up, you may actually make yourself more, not less, uncomfortable in the end. That said, you may have to fiddle with the tilt of the bars to find the most comfortable position for your hands and wrists.
Good luck and have fun!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher