I ran this a few weeks ago but my watch died before the data could be uploaded. Total time was 4:02:33 for Sign to sign (i added a bit just to make it a full marathon). Done counterclockwise.
It's a fun climb up to Flattop Mountain, but the descent really takes it out of you (or me at least) so it was still slower than expected. No doubt some speedster could take 15 or 20 minutes off this.
North Inlet JCT: 1:01:40
Flattop JCT: 2:02:57
Haynach JCT: 2:39:09
Green Mtn Jct: 3:25 ish