Dressing for the Blue Ridge Marathon is harder than dressing for almost any other road marathon, because you're not running at one elevation. The temperature can swing 10 to 15 degrees between the valley and the summits.
Climbing generates enormous heat. Even on a cool day, a two-mile sustained climb will have you sweating through whatever you're wearing. The temptation is to shed layers at the first climb. The problem: the summits and ridgelines are windy and cold.
A light, moisture-wicking long-sleeve base layer works well for the start and the summits. Push the sleeves up on the climbs. Pull them back down on the descents. An ultralight windbreaker or vest that you can stuff into a waistband is worth its weight for the exposed Parkway sections.
Yes, even in April. The Mill Mountain Star and the Roanoke Mountain summit are exposed and windy. On a cool day, bare hands on the ridgeline at 2,000+ feet are uncomfortable.
The course is entirely paved, but the pavement varies. Road shoes with moderate cushioning are the right call. You want enough cushion to absorb the pounding of 3,860 feet of descent, and enough grip that you feel secure on the steeper sections.
A small handheld bottle or a hydration vest gives you insurance on the Parkway climbs, where you're working the hardest and sweating the most.
The short version: Layer for 45 at the top and 60 at the bottom. Carry what you can adjust. Leave the ego at home and bring the gloves.