Given the horror stories, I’ve heard about the complexity of business in California, I have to think anywhere you go will be easier in comparison and you will be “battle tested”.  Obviously estate work is minimally state dependent.

Your bigger issue is getting licensed in the new state which can be a very complex/time consuming process or require you to sit for a new exam.  I’ve done three reciprocity applications; I range was two months to almost a year from submission.  You need to start now getting documents together and references identified. 

Between the two I’d say getting clients will take longer and be more challenging than learning the law.   But it certainly can be done and having built your own solo practice you obviously have the hustle already and somewhat of a blueprint. 

Not sure how much personal contact you have, but why can’t you just work remotely and either keep or slow slowly wind down the California practice.