How to always log in as player mode?

I'm decently new to using Roll20, sorry for my noobishness. Recently a game owner and I decided to swap places permanently, so he promoted me to DM while he owns the game itself.  The issue is that he wants to always join the game as a player so that he doesn't see any surprises before they come, which is hard when he always logs in as a GM and not as a player.  How does one enter their own games as players instead of having to click 'Re-join as player', which allows for a five second window of accidental viewing of whatever the DM's working on?  Thanks for the help.

If you right click the "Rejoin as Player" button in the Settings tab, you can get an "as a player" link to bookmark and use to join the game.  That will always put you into the game as a Player.

you can also set up a 'landing page' for everyone to log into - then when all are ready you move them to the the current page for your adventure. THere are a couple threads about this floating around for your viewing pleasure.