With the bone-dry trails, the Moots Vamoots RSL road racing bike makes a very comfortable cyclocross bike. Fatter tires would be a big plus, maybe a 28mm tire would fit, but I’m not sure.
I rode the Vamoots RSL up Black Mountain a few times (SF Bay Area) and really enjoyed myself and the way the bike accelerated. One has to have some finesse on road-racing tires to come down the loose gravel and such, but no big deal. Helps to have MTB experience, I don’t advise such adventures for those versed only in road-riding.
I’ve had enough SRAM Red shifting to last me for a long time.
My on-order Moots Vamoots RSL and Moots Pyschlo X RSL will both use Shimano DuraAce DI2 electronic shifting (bike below is an evaluation bike). The Pyschlo X RSL will use an XTR 11-36 cassette with a modified DI2 rear derailleur.
The Lightweight VR8 front wheel and Lightweight Obermayer rear wheel turn out to be exceptionally comfortable for trail use. I can’t say how they would stand up to continuous duty, but they were perfectly happy on my trial runs.