If I may, I'd like to recommend the FREE MapQuest app. It will give you turn by turn navigation and it is FREE. If it may be suitable for your needs, you can download MapQuest from the App Store.
Now, for your questions: after you've Added the destination point, click on route. You should see the blue line leading from your start point to the destination. Now select START. Afterwards, you will see the directions at the top of the Maps app. As for saving your routes for future reference, I 'think' it does it on its own because my previous routes show up when I tap on the space to enter a destination. As for the pin drop, I don't ever use it so I'm not sure.
Just Me, D
Tapatalk (iPhone 4S)