Here is the elevation profile for my upcoming trip:
The grapevine is steep but once I pass that it's nearly flat. Also I'll only be going north where the uphill is less steep. I'm not too worried about the downhill, as I'll go very slow at high RPM and likely won't even need to use the cars (brand new) braking system. The braking system on the trailer is also brand new and rated for about twice the weight it will be controlling... and most importantly everything has brand new high boiling point fluid.