I'm not sure what Trump has to do with any of this or why literally anyone but his close family would think anything good would come from that conman no matter what your politics are.
That and some of them are unhappy about living in the same state with people who have different skin color or sexual orientation and having their government pay for schools that teach science, women’s reproductive health, social safety net programs, and so on.
The less populated parts of the state get dramatically disproportionate state and federal resources spent on them. Support for their schools, infrastructure, medical care, fire protection, etc.
Most counties in California should be very pleased to be thrown in with the coastal urban areas, because without them the state economy wouldn't amount to a hill of beans. All of the resource extraction industries (logging, oil, quarrying) and agriculture+fishing combined are worth about 5% of the state economy. The "State of Jefferson" counties wouldn't even be able to afford to pave their highways, much less fight their wildfires, and certainly not rebuild Oroville Dam.