We took the 15 to 210 to the 5 to return to Santa Clarita once last year on a Sunday fairly early in the day. We used that rout instead of Pearblossom due to a fire off of the 14 that had traffic snarled. The route - not towing - took us about 10 longer than the Pearblossom route but I was running 80+ for most of it. Not entirely practical given you are towing (I assume). For us the distance was longer but the higher speed allowed nealy the same time. From Ventura, you'd still need to get from the 210 to the 101 in some manner - i.e. take the 5 via 126 (another "death highway").
In making 20+ trips to Havasu each year for the last 3 years I will still take Pearblossom unless I know from traffic or weather reports that it'll be a slower route.