I use Google My Maps to pin locations first. Then import the data to Maps.me to create custom offline maps. For my android phone and tablet.

https://support.google.com/mymaps/?hl=en#topic=3188329

http://maps.me/en/home

http://www.kevinandamanda.com/create...h-google-maps/

Takes a little work. Wish there is an app that can streamline the whole process. Better yet, wish Google My Maps can be used offline.