m in israel: The only halacha that has relevance to this is that a man should not walk behind a woman. Anything added on to that (i.e. Opening doors, which is somewhat related to the halacha but definitely can be done in accordance with it) is a stringency. Thus, as I stated in my first post, there is no reason a man should take this upon himself (Not opening a door) before being dedicated to observing all the mitzvos in the torah first. Obviously,for a man to walk behind a woman is wrong, is a halacha, and is NOT a stringency. I hope this clears everything up.
It is important to know that people in different circles do different things, so what some may consider improper, others consider proper. Do what you, and your date, are most comfortable with.