I'm aware of that, and indeed participated in that AARoads thread.
I'm busy with other stuff this week, but once I've dealt with the impending CA 58 reroute in Bakersfield (hope the bad weather doesn't interfere) I'll try to address this. I'm leaning to adding the Colorado Street extension somehow, not sure it should be added to usai as we did with the separate route 5S in Newhall (added as I-5 Truck).