Yes, you are entitled to receive copies of your father's Will and Trust. As an heir-at-law to your father, you are entitled to a copy of those documents even if you are not named as a beneficiary. If wife refuses to give them to you, then you need to file a Petition to compel the documents with the Probate Court and the Court will then order wife to hand them over. There is no way to force wife to hand over the documents without a Court order. But you can tell her that you plan on going to Court for an order if she does not provide them voluntarily, maybe that will do the trick.
Because your father has passed away, your locality will likely require the will to be filed with the local surrogate (probate) court. It is then a public record, and you and anyone else would be entitled to a copy.
I agree with Mr. Davidson - the California Probate Code specifically gives you the right to receive a copy of the trust IF it (or part of it) became irrevocable upon your father's death. If your stepmother will not release a copy of it, you can compel her to do so. Of course, that will probably make her upset and angry with you, so you need to decide whether you are risking more by asking for a copy. But if you believe she would never leave you anything anyway, you might as well see what your father did.
The information you obtain at this site is not, nor is it intended to be, legal advice. You should consult an attorney for individual advice regarding your own situation.