He could declare an emergency to get 60 billion to build a useless 2000 mile fence the Mexicans will tunnel under. He could steal money from the old, sick and vulnerable so he can give tax breaks to his rich buddies. He could start useless trade wars that will decimate the agricultural sector and cost billions in farm aid and drive up the cost of housing/construction via the cost of steel, aluminum and copper. When he's done shoveling all the money he's borrowing out the door, his poor policies and financial "reform", which consists of undoing everything Obama did to stabilize the stock market, will leave America in the lurch when the markets eventually tank and millions of retirees lose their savings again, while CEOs and financiers get bonuses instead of going to prison where they belong. He could systematically decimate the EPA, and destroy long standing relationships with allies, get laughed at by world leaders and reduce America's status on the world stage to a laughing stock. Oh, wait, it's too late. There really isn't much more he can do...or is there? I bet he can find new and innovative ways to cramp his little mushroom dick up the already battered ass of America.
I would say that California being booted won't even be on his radar unless it's a distraction while he steals whatever isn't nailed down.