I have now Neptune transiting my first house.
Actually, it's difficult to realize the exact moment that Neptune transits your ASC because it is so slow that its transformation last for some several years.
I can relate to the often described isolation feeling of Neptune when it was finishing its tweltth house transit. Actually it felt it stronger and stronger but as a certain point, I was filled with much idealism, sensitivity, spirituality, poetry, (some depression too), and an inner connection, without realizing. This took me about 4 years. When it was around the ASC I even experimented with psychedelic plants, and did much artistic stuff. Since my ASC is mid Aquarius, I had already Uranus transiting my first house at that time, and both Uranus and Neptune crossing my ASC were moments of much openness to the world, and inner revolutions.
In these last 6 years that Neptune has been transiting my first house, I am filled with great ideals, mostly connected to help mankind or the planet, and I actually do stuff for this. I feel different and unique but that's not a problem for me.For the past 5 years I also felt very confused in my professional direction, so confused. Recently, I finally realized I had to do something meanigful and mainly live in the moment, and stay connected to my inner yearnings. I guess Neptune transiting the first house is all about this. Rediscovering your inner world. Certainly, I discovered a much richer inner world from what I experienced 10 years ago!