The most passable trans woman in the world is a man in a dress. It's just that he is better disguised as a woman than others of us. If I could really pass I would probably try simply because I would have more freedom to dress in my favorite styles and fabrics in public without feeling that I'm drawing attention to myself or that someone I know might see me and I'd be embarrassed by my attire. Since I can't adequately masquerade as a woman I've taken to dressing in my most feminine clothing at home and wearing skirts occasionally in public - and more frequently on private walks.
Doing the public man-in-a-skirt thing has been an interesting challenge; I would suggest that more crossdressers try it. It's quite a lot of fun trying to get a less-than conspicuous "masculine" look out of a skirt. You start with a kilt.. and of course who is to know what you're wearing underneath.
