I've been using these features in private for a while, waiting eagerly for it to become public! Now I can use this when other people are around, and tell them about it :)
One thing that could trip you up: When you're offline and using an offline map area, you can only get directions to places within that offline area. If you're in the city and going out to the mountains for the day, an easy mistake to make is to just download an offline map for the mountain area where you think there will be no cell coverage. You want to include the city in the offline area you download, if you will want to get directions *from* the mountains back to somewhere in the city later.