Narrow driveway, pull in or back in?

Backing in will be easier. There is more overhang at the back of the trailer than there is at the front of the truck. This allows you to "cheat" by having a large section of the back of your trailer go over the lawn w/o any wheels touching the lawn. You could have quite a bit of trailer well on it's way up the driveway before the wheels hit the actual driveway surface. Some maneuvering will be required. It probably won't work in one fluid motion, at least not in the beginning. With practice, who knows?
This assumes there are no posts, signs, trees, etc right adjacent to the end of your driveway. None were mentioned.