Hestaby's been around for a long time, just not mentioned terribly often. She's essentially the big stick that keeps the border between the Tir and the California Free State from erupting into warfare (again). She was known for being a pretty kickin' mage, even by Dragon standards, and the Shasta region that she lived in was a major power line access point. You can see her post in older books as Orange Queen (The Shasta region grows oranges, you see), where she puts her good sense of humor to work whapping Harlequin on a regular basis. After Dunk died, she stepped up as the limelight dragon, happy to talk to the media and to start doing good PR work, talking against racism, promoting the 'lesser races' and so on. There's some discussion about how much of this she really believes in and how much is a show.
Her situation got pretty bad lately when she called out Sirrurg on international television and supported his being drug before the UN for a war crimes tribunal. This, and generally flying in the face of Lofwyr, got her set against ol' Golden Snout during te recent Dragon War and, well, she lost. As punishment, she was stripped of her horde, her followers were killed (The ones that could be found, at least), and she was banished from her Shasta lair. She's probably banished from her other (known) lairs as well.
This has given rise to a running joke that she's hitchhiking through California, going to Burning Man, surfing, competing in Hackey-Sack tournaments, and so on. In non-joke time, her activities post-banishment are unknown.