How can I be the best Long distance mother in law?

I have 2 son in laws that live near me and that I adore and who love me. Although they think I’m crazy sometimes.
My son recently married his girlfriend (and mother of my grandson.)
They live 1000 miles away.
My son is bi polar, so he does not always present me in the most favorable light. (Although his memory is more favorable now that he lives so far away.)
I know she already has some false assumptions about me, as well as the natural apprehension most daughter in laws have about their mother in laws.
What I really need, are ideas for ways to communicate love, acceptance, confidence and trust that are not sappy or over done.
I really do love her and I think she is doing a great job with my grandson. I know that my son is not the easiest person to be in a relationship with and I want to be a to support her without her worrying about my being judgmental.
Any ideas for things I can do from 1000 miles away that will build trust? I would love to build a loving relationship with her and love her like a daughter.