Considering the premiere of Season 5 is almost a year away I'd take any reports on what it'll be about with LESS than a grain of salt.
I really doubt the show will movie production away from Georgia so I suspect we'll be here for the long haul. They *might* be able to using Georgia locations to match locations in other parts of the country if they head for Alexandria/D.C. But... It'd be a stretch.
As for the guy with the radio and the importance it plays in the comics, they may not translate to the show itself. He likely had it just to reproduce the comic cover they were going for on the introduction of the characters. He simply has to communicate with their camp.
All speculation on part, naturally, but I think it'd be hard for the show to depict Alexandria/D.C. while keeping production in Georgia and not having to do some extensive, and expensive, location shooting.
Several articles I've read and even an interview with Michael Cudlitz says they will follow his(and his crew) background that story line (The trip to D.C.) pretty much verbatim.