I have heard of relationships that did great and others that did not. I know of one young man from our area that is a 2015 graduate and just got married to his girlfriend back here in Ohio. That relationship worked. Many have, many have not. The relationship question is so subjective and dependent upon the 2 individuals in that relationship.
As far as communication, there will be none during basic with the exception of Doolie Day Out. You may get a phone call that day. Only snail mail or Write2Them until A-Day. After that it will be squadron specific as far as when, where and how much they can use their phones. Generally, there is regular but limited communication during the academic year. I will just caution you to prepare yourself for things to be very different. Her social time will be extremely limited, especially the 4* year. I don't intend to discourage you, I'm just trying to help you with the reality of life at the Academy and your relationship with any Cadet, esp. the 4* year. It can work. I believe it takes a lot of maturity and 2 individuals that are secure and confident in their relationship. I wish you both the very best !