I enjoyed parking on the streets West of the stadium. Short walk and easy access to the stadium via the south west entrance.
But use common sense and dont give anyone a reason to break into you vehicle, park by a light if you can, or park in a paid lot. Some charge 5-20 bucks.
Oh and its little to no traffic if you're heading towards downtown, medical center, montrose, or east side via the streets, after the game.