Patient Portal. Electronic Messaging is fast and easy utilizing the NextGen Patient Portal, just enroll with the links above and you'll have access to many features that make communicating with GTOC easier than ever. ... Traverse City Local: (231) 947-6246 Toll Free: (800) 968-6612. Mon - Fri: 8:00 AM - 5:00 PM. 929 Business Park Drive Traverse ....