Many would say "getting lost" is part of the fun of driving on a Greek Island but this Selected Tour might be of use to visualise and plan your holiday.
The route is displayed as a Fly Over video which you can see here by Selecting "Fly Over" above, then a Sat Nav of the same route and finally you may Select "View Elevation" above to see just how "bumpy" these Islands can be.
As far as using the Sat Nav "point to point" while driving is concerned this route is only "on paper" at present and has not been updated in conjuction with a Car Hire company who knows the roads of the Island better than the Google algorithms. You should use it WITH CAUTION and modify it as you wish to suit your own plans.
You should also Download a Map for Offline for the Island in case the Mobile Coverage might be inadequate or unknown. Open the link and in the MENU select "Map for Offline" and follow the prompts (only works on a mobile device).