I can't say I have found shortcuts, but one or two alternatives that are way safer in certain areas. The biggest one is once I cross the bridge into the city, the bike lane ends at the first traffic light.

When I started commuting, I would cut through 2 traffic lanes to turn left at the light, then the first right. It was horrible.

Learned from a friend that I can turn right after the bridge and go past the USC baseball stadium, and wind my way through the sorority housing area. It was better, it added some time, but it still wasn't great. There are trains that sometimes stop and block one of those roads for a very long time. Plus, it did put you on a busy road for a short stretch.

Once you cross the bridge and reach the light, if you go straight you go up an overpass that goes over some RR tracks (it's very steep, and there is usually a lot of traffic and no shoulder). However, it took me awhile to find this, and I think it is only possible because of some new student housing, but I can go straight at the light and go under the overpass and that brings me to some new luxury student housing and I can go from there.

Attached photo: original route in red, 2nd in blue, winner winner chicken dinner in yellow