I too am the "Dude in a dress". I won't pass - not now, not ever. The mustache is a bit much, even for women of a certain age and a Mediterranean background. I like my 'stache, I've had it for more than 40 years and don't think I want to remove it. I also adore women's clothes, from featherweight fabric tops to the heels. Like you, oh gentle OP, I want to wear what I want. I have been sneaking up on this point for a while; I shave my legs, I wear paint on my toe nails, underdress because I like the fabrics and the feeling of it all. In the last year and half, with much support from my SO, I have actually begun to wear skirts in public. The outings have been sporadic to be sure, but they have occurred. As an aside, friends know of my desire to wear womens clothing and I was offered the opportunity by the hostess to attend a formal gathering in a dress, as long as the dress met the required color scheme she set forth for all the womens clothing. Alas, a previous commitment precluded that from happening, but the exhilaration and abject fear that invitation brought forth was almost overwhelming.
I try to dress age appropriate, with a skirt, heels and hose and usually a mans dress shirt. The outings have been in the day time and I have discovered, like a good portion of the posters on this site have said, that the most difficult part is overcoming the fear that we have in our heads. Obviously the world is still spinning, the sun still comes up in the east and at least in my case, I haven't been stuck down with a bolt of lightening out of a cloudless blue sky for appearing in public in a skirt and heels.
Our desire (to wear what we want) is in some cases a far easier challenge to overcome than the torment that some of the women on this site are going through in their search for their own truths. For that I am grateful. We still have the social stigma to overcome, but it can be done. Another responder to this thread mentioned skirtcafe.org, it is also a wonderful site for those of us who identify as male, or mostly male, and wish to wear the clothing of the opposite gender. Both sites (this one and skirtcafe) offer support and encouragement to those of us who are willing to search for our own truths about who we are, and where we think we would like to go on our journey. I am going to suggest that you start wearing the skirts and dresses that you want to. It's frightening beyond belief the first couple of times, but is also liberating and empowering at the same time. It seems to be working for me so far, I hope it will for you as well.