Your interest in requesting a platform based on locale isn't wrong in itself, but you're going about it bass-ackwards. The short, non-scientific answer to your question: there's 10 Fleet VAW squadrons, a typical RAG class sends one dude to each squadron, so you have very roughly 10% chance of going to CAG Five out of -120. But of course that's not taking into account anything else, and there are always other factors, not least 'needs of the Navy'. And as others have said, dream-sheeting a community because of a small chance to go somewhere for three years out of a career is poor beadwork.
Instead, look at where you're most likely to be homeported in each community and use that as one factor in your thinking. VFA gets you several years in Fresno or Virginia Beach. VAQ, you're guaranteed the misty coolness of the PacNorWest. Going E-2s, 90% chance of being in Norfolk or Ventura County. You get the idea. When you finally get flight-side, talk to instructors from the different communities about what life's like, including but not limited to QOL when you're home.
A tour in Japan at some point in your career is certainly doable, whether as a nugget or DH, or a Boat tour, or some staff, no matter what community you go to. Everyone I've known who's done a Japan tour enjoyed it, personally and professionally. More often than not, though, they have to draft guys to go, so being eager and willing to jump on an FDNF billet should the opportunity arise is a good thing. File "I'd like to do a tour in Japan at some point" away in your headspace, concentrate on getting through the program in P'cola, and look at probabilities vice possibilities.
