Yeah, there's a lot of traffic, some degree of risk above normal, squids, trucks, etc., and very nice -- and less touristy -- roads all around the western NC, eastern TN, and northern GA area.
That said, one of the nice things, IMHO, about the GAP is that two or three photographers camp out at the few pull-out areas. And so if you want to get what are typically high-quality shots of you on your bike, this is one way to do it (track days generally being another way).
As luck would have, one of my daughters lives in Asheville, about a two-hour ride away. Every time I get a new bike, I happen to schedule a ride down from NY to visit her for a few days, and then take a day off for a Gap day, so I can get some new-bike pics. And the ride down to that area from Asheville is a nice warm-up. If you do the Gap mid-week, and get there, say, 10am, it's been my experience that traffic is not bad.
In my gallery of my now-sold XCT, I have a few pics that I took at the Gap's one large pull-out, followed by a few of the pics taken by the Gap photogs (I buy the packages from them all), starting here: 2012 Victory Cross Country Tour