On June 6th, 2020 I went Gate-to-Gate on Mailbox Peak in 1hr 19min 54sec via the Old Trail. Starting at the lower gate, up old trail, tagging the mailbox at the summit, and returning the same way.
As Uli pointed out in the comments on this route, there are two gates. As best I can tell, both Dan's ascent time and and Fabien's gate-gate time both were from the Lower gate, so that is where I started/stopped at as well.
Just as a note, my ascent only time was 53min 55sec. Nowhere close to Dan Kraft's INSANE 49min ascent. Holy nuts he must have been hauling. Thanks for the future motivation Dan!