Here in the urban northeast US people won't look twice if you're wearing abaya--no big deal. In general, the northeast corridor (Boston-New York-Philly-DC) and the urban areas of the West Coast are very open and people wear all sorts of different things. The large cities in Texas (Houston, Dallas) as well places with large universities (Austin, TX), are also diverse and abaya is no biggie. Finally, the Detroit area is home to a very large and very good university (University of Michigan) as well as the country's largest Arab population, so you would probably not feel out of place there.