After you get her SSN, get her on your banks account as joint holder, get her a debit card and both of you use that account for all your spending, bills, etc. (if possible with your financial setup). Also start getting her on utility bills, on your employer health insurance (after you're married if applicable). These are all good evidence of co-mingling your lives financially for the Adjustment of Status process. Our interviewing officer at USCIS said something along the lines of, "I see you pay everything out of your XXXXX Bank Checking Account." They look at these things closely. Also wills, medical power of attorney, etc. are all good things to have in general and make for good evidence on your AOS application.