I've day hiked the MR 2 years ago and came down the main route and we didn't even start as early as 2am.

Definitely study the route as it is less traveled and not maintained. The most confusing parts will be navigating the E-Ledges for the first time and the area from before Lower Boy Scout 'Lake' (LBSL) to Upper Boy Scout Lake (UBSL).

The Mountaineers Route from UBSL can also be confusing. I used AllTrails to help me with this.