I lived in Asheville, NC (milepost 358 on BRP) for a few years, so perhaps I can help you. As mentioned, temps and road conditions vary greatly on both BRP and SLD. I was in the area last week and there's still a fair amount of snow on the "backside" of the mountains, where there is little or no sun in the winter. Once on a mid-summer ride, it was 85+ when we left my house. Thirty miles later, on top of Mt. Mitchell, it was 35 degrees.
Both roads are well maintained and the authorities will usually close sections that are risky. So you just follow the detour signs, get back on and motor on.
As for LOE, they are patrolled by Federal Agents, which, believe it or not, is a good thing because if you get busted for being a little too enthusiastic, the offense will not go on your driving record. Obviously, if you're going triple digits, then it's definetaly a bad thing. I always like to ride "The Pace" on those roads - awesome sweeping curves.