sharing network over usb at boot

BeagleBone Black running Debian connected to Windows 8 PC via USB. Following the instructions in I got BBB to connect to the internet.

The issue is that I can not figure out how to get the route added at boot.

I added /sbin/route add default gw into /etc/rc.local before the exit 0 but then systemctl reports that rc.local.service failed and the route does not get added. I verified that putting something like /bin/ps aux > /tmp/ works correctly in /etc/rc.local

Adding /sbin/route … to the .profile for root works correctly when I ssh in to root.

Thank you for any help.