That’s certainly a liberal interpretation of warm up… If you’re in Dahlonega, the ride over Woody Gap to Suches is a nice long, but gentler climb and you could add Wolf Pen too. Plenty of parking on 19 near 60 where Woody begins.
Brasstown is a brutal climb if your gearing isn’t sufficiently low and there’s no such thing as riding it “easy”. Not sure it’s a good warm up climb. But maybe worth it just to have the experience.