This is the best way I have figured out to get maps from Google maps to my Garmin.
1. Install a program called Tyre from
http://www.tyretotravel.com/download-tyre/download-tyre-basic/ (the free version works fine)
2. This is the way it works best for me. Open Tyre, go to tools, preferences. Go to the Google Maps-Route tab. Make sure Drive and Motorbike are selected. On the General Tab you have the option to make the default GPS Garmin. Leave it on TomTom even if you have a Garmin. Select OK
3. Go to Google Maps (MUST BE CLASSIC VERSION. NEW GOOGLE MAPS DOES NOT WORK) Click directions, put your 2 locations in and click Get Directions. Do NOT drag the route. Anywhere that you want the route to take a particular road/route right click on the road and select Add Destination. Once route is completed click the chainlink icon right next to the printer icon. Copy the url that is on the popout window.
4. Go back to the Tyre program and click File, Import from web. A window opens, paste the url you copied from Google maps into the address section where it says http:// and hit enter on keyboard.
5. You will see your route. In the bottom right corner click import. A little window pops up select waypoints. Your route should be visible in Tyre now just as it was in Google Maps.
6. Now plug your Garmin into the computer using the mini USB cable. It will be recognized by Tyre. Your menu now at the top of Tyre should say Garmin instead of TomTom. Select Garmin, Copy to Garmin.
7. Once copied to the Garmin unplug from computer and do the usual import of a custom route on your Garmin.
THIS WILL NOT WORK WITH NEW GOOGLE MAPS. FEEL FREE TO PLAY WITH OTHER SETTINGS BUT THIS IS THE COMBONATION THAT I HAVE FOUND WORKS BEST.
When plugging in your Garmin for the first time there may be a couple of other questions you answer. Don't really remember.
Hope this helps, John