Multi-State Trusts

I was speaking with a client recently who has assets in several other states, although she lives in California.  The easiest thing for me as an estate planner is for the client to "move" all her assets to California.  That way, California law applies across the board, and I know I can draft for the result I want. But sometimes a clients wants to keep that property in another state .   This complicates things.  Does the law of California or the law of the other state govern the transfer of the non-California property?  Does the other state recognize the validity of a California trust?  If it does, will it administer the California trust using California law if that law conflicts with [...]