Mt Mitchell (6684') is the highest peak in the eastern USA.
The ascent from Briar Bottom is gains nearly 3700' in about 5.25 miles. Start at the Briar Bottom TH, for the ascent time stops at observation deck. While there is a Strava segment for this, it is important to report your actual (watch) time, as relying on GPS can be off by many seconds. Also, the Strava Segment doesn't go to the actual observation deck.
I started both my attempts at the 0.0 sign on the bridge on the parking lot side of the river. The GPX provided on this page starts a little farther up the trail but that seemed like the logical beginning to me, as it is where they begin marking the trail.