I am a MS1 at UCONN and did the postbacc program.
I do believe there is a preference for in-state or regional students or at least people with some ties to the area, but there where students in my post-bacc class from other parts of the country. It is a very small program - about 15 students total in the one and two year programs. I absolutely loved the program and would recommend it highly. I was told that about 85% of the students are accepted into UCONN's med school. This varies from year to year. My class was smaller than normal and two of the candidates decided to take another year to pursue other interests before applying. The MS2 class has a bunch of former post-baccs in it.
If you have any questions feel free to PM me, but the best source of info is Dr. Keat Sanford, the program director.