For my last trip to Argentina, I created my first custom maps with My Maps for my android phone and tablet. But they needed an (speedy) internet connection. So I imported My Maps' POIs to an offline map app, Maps.me. Using both was a game changer for me. I didn't have to lug around (hard copy and online) guide books and cheat sheets, with and without an internet connection.

Maps.me does not support My Maps' layers and variety of pin icons, which I like a lot. An annoyance.

Have yet to try Here maps to see if it can. Here is also for phone only.

Here's the tutorial that got me started, and there are plenty more online and in youtube.

http://www.kevinandamanda.com/whatsn...ogle-maps.html