If you really want to have a formal advising relationship during your gap year, just work to establish a good rapport with the advisers at your institution before you leave. That way, regardless of what the official policy may or may not be, they won't mind helping you out for the period of time when you may not have as strong of an official connection to the institution.
That being said, I really don't understand the value of advisers. I'm guessing that's just because I haven't had a great personal experience with them. I got burned by my college counselor at my high school and won't trust people whose sole or primary job responsibility is advising ever again. The medical school application process is too important to take any one person's word for anything significant regardless of their position. SDN and the internet in general makes it so easy to do your own research. Advisers can contribute their input and can also contribute valuable advice specific to your institution, but really, they're not that important.
The only exception to this - the only really really important function of premed advising offices is to compile your committee letter of reference.