In San Francisco, my main boarding port, there is a separate waiting area for Elite/Platinum, but even if you're the 1st in the terminal, people are crowd around the boarding door, so from my experience it doesn't really matter when you board as people have entered 45 minutes after I did & still boarded first.
Suggestion from my experience, in San Francisco, is to get there before they open up the terminal & I've never experienced a long line into the terminal as others have had boarding later.
Tom