You can download my Google trail maps if you use the Google Maps app on you phone in combination with the My Maps service for Google accounts. (Here are instructions for Android users, and iOS users).
From a user: “To prepare before I left, I maximized the Google map embedded on your website on my laptop and then clicked ‘copy map’ to make a copy in My Maps for my Google account from the 3-dot menu near the search button:
From there, I was able to open it in the Google Maps app on my phone following the instructions linked above.
Now, if I wanted to download the tracks and points for use in a dedicated GPS device, I would select the “Download KML” option from that same 3-dot menu above on your map. It will download everything into a KMZ file on your computer. From there you can convert the data to GPX (used by most GPS devices) using an online service. I have personally had good luck with the “MyGeodata Converter” for KMZ to GPX conversions. Getting the GPX files from there onto a GPS device will vary by device, of course.”
Thank you, Jason!