Google quietly announced on Google+ and in the Google Maps Help forum that the new version of Google Maps for Android now supports bringing over your custom My Maps into your app.
Google said, "Take your custom maps to go: Rolling out today, view your My Maps on the latest Google Maps for Android."
My Maps are maps you create in Google Maps web or the app that might plot out things for you or custom maps you make. These are now visible in your Google Maps app for Android. To turn it on:
1. Open the Google Maps app.
2. Touch the side menu > Your places.
3. Scroll down to see your My Maps.
4. Touch one to show it on the map.
There are detailed instructions on how it works over here.
So for all you maps lovers out there, give it a try.
Forum discussion at Google+ and Google Maps Help.