I teach and recently relocated, so I've been where you are. :)
Best thing to do is to make some calls to the local schools, in the area you're looking at, and tell them your situation. I only needed a resume for job fairs and interviews. In order to be considered here, I had to put in an online application. Once the application was in, principals could review it to see if I fit the needed positions they were offering. Because it was competitive I had to make some calls in order to get my name out there and get them to take a closer look at my application. I got many interviews this way and was offered a few positions. This was just last year when jobs were beginning to become scarce in education as budget cuts were being made. It's not easy, but it can be done.
I wouldn't use a PO Box because it will eventually come out somehow (interview, when offer is made, etc.) that you are relocating. Why not be upfront and honest about that? Principals like that and many principals I interviewed with wanted to know why I wanted to relocate (my husband's job) and if I planned on settling in the area and making roots there. As long as they know you won't just up and leave, they will give you a chance.
Good luck to you and yours!