How about making your top 10 pages mobile-friendly? Ask someone on your team to list your top 10 website pages based on page views. Then ask them to run those pages through the mobile-friendly test.
Google doesn't care if you are using responsive web design (RWD) or an m.website to provide for your smartphones. These are two of the most popular technical ways to serve up a mobile website. You can tell if a website uses RWD by using the browser on your laptop. Take the browser window with your cursor and drag it into the top left corner of your screen, making it as small as possible. If the website reformats automatically along the way-from laptop size to tablet size to smartphone size-it's a responsive website.
Philip King is founder of The Donation Funnel Project, an experiment in online and mobile fundraising. He is a regular contributor to NonProfit PRO.