The Century Freeway (105) is usually a good alternative to the 405. It starts at LAX and goes all the way to the 605, which you can take north for a couple miles and then ride I-5 all the way down to the stadium or go 605 south to the Riverside Freeway east (91) and rejoin I-5 south in Buena Park. This is somewhat less roundabout than going all the way down to 22.

There are a lot of "Disneyland buses" that run from LAX that will put you within taxi, or possibly hotel shuttle distance. Another non-automobile alternative is the Amtrak or Metrolink train; the Anaheim station is just north of the stadium. The trick is getting from LAX to a train station. Unfortunately, the Green Line doesn't connect to the Norwalk Metrolink station so you need to go up to Union Station downtown, an hour by Metrorail (two transfers) or an hour and a half by bus (direct).