Oh that brings back memories....
When I first hired into the
Disneyland Resort, I was attending CSUF and living in the Dormitories over there. I used both of the routes you described to get to and from work before I bought a car, lol.
Each route combination has it's good and bad parts. 26/43 gets you to DLR faster and drops you off at the Main Entrance, but 26 isn't a 24 hour route. 57/50 is a bit slower and you have to hike it, but it does run all night.
If you're looking in OCTA's trip planner, the 26/43 bus stops are "COMMONWEALTH -NUTWOOD" in Fullerton for CSUF (this is on the north side of Nutwood, in front of Langsdorf Hall) and "HARBOR-EAST SHUTTLE AREA" in Anaheim for DLR. The 57/50 bus stops are "HARBOR-KATELLA" in Anaheim for DLR and "STATE COLLEGE-NUTWOOD" in Fullerton for CSUF (this is on the far side of the Nutwood Parking Structure, near the TSU).
There's also an additional shuttle that meets incoming Metrolink trains on weekday mornings at the Anaheim Station and stops at various points throughout the Anaheim Resort Area. A few of the Full Time Cast Members in my area who lived in Los Angeles used it regularly.