@Just-Lisa-Now- 

May your prospective client not be MFJ with a spouse who moved into California at the same time he moved out.  

This reminded me of a Wisconsin case back in 1988 -- the court there decided that the state could not tax sale of residence when gain was carried over to a new one out of state, while allowing the deferral of gain for in-state residences.  But it said that it was OK to deny moving-expense deductions to those moving out of state, while allowing them to those moving to or within the state.  This is just one state's mid-level appeals court, so it's not really precedent for others elsewhere. 

https://law.justia.com/cases/wisconsin/court-of-appeals/1988/86-0372-6.html