Best route to IRG 3 (by way of Danville, CA)

We will be leaving this weekend, heading to IRG3. I have been reviewing various routes. If I were not pulling a trailer, I would take I10 to Los Angeles, catch I5 the rest of the way to Danville. However, the speed limit in California when pulling a trailer is 55 mph. So, I'm considering heading up US 93 to Las Vegas, then US 95 to Tonopah, NV, then west on US 6 / CA 120 to Danville. It adds 100 miles to the trip, but should take less time going 65 rather than 55.
Has anybody done this before?
Edit: Starting point is Phoenix, AZ
Has anybody done this before?

Edit: Starting point is Phoenix, AZ