Been to three games this year. Trax is a joke. Way too busy 90 min before the game. My friend said 3 trains passed him before he could get on they were so busy.
So there are some businesses in research park that you could park at. They say tow away zone, but it only applies during business hours. This is a good option because after the game you can walk up 500 south because they block any traffic from coming down the street.
Anywhere west of 500 south on 1300 east is a good place.
For the Arizona game, I parked around the park on South Temple and University Street.
Lots of free parking. not a bad walk from anywhere.