Transfer was finalized this week!
We worked with one of Vanguard's concierge associates, who provided a phone number directly to his office. Very helpful and friendly guy. Made the whole transfer process smooth as silk.
Cost basis was easy to figure out, since all of her taxable investments were made this year. It came from a life insurance policy she collected after my father passed away.
I have all of the taxable transactions saved as PDF's on my computer.
Yesterday, we made our first transaction with Vanguard's brokerage service. We're gradually liquidating the IRA ETF's and switching them into Vanguard Admiral funds. Happy to say that they were very patient and informative, as I have never traded an actual stock before... only bought/sold mutual funds. Got a quick intro into bid/ask/stop orders and whatnot.
I have to tell you, overall I have nothing but good things to say about Vanguard's level of service. Even when I started out with my own personal relatively puny accounts, I remember communicating back and forth with Vanguards associates and walking away feeling that they were genuinely trying to provide me with the very best advice. My first phone call, I actually spent over an hour with them (maybe two?) and hadn't actually made any transaction by the end of the conversation. Nor did I feel any pressure to do so. About a week or so later, I began transferring all my other investments over to Vanguard and have not looked back since.