Senior Citizen newbie programming question!

Greetings ladies and gentlemen. I am no longer in school, in fact I'm in my sixties! I have done some programming in my time, but nothing in the Android arena.  Most has been vb6 with a smattering of C sharp  and oop thrown in. I stumbled across the App Inventor and would love to give it a try just for fun. Most of my programming would be done on a tablet. The drag and drop functionality of AI would seem to be tailor-made for a new "hobby". My question is this. After using the blocks editor et. al to build an application, would I have access to the raw code, directories, xml, manifest etc.  Can I use app Inventor to assemble a starting structure for a program, and then augment the java code manually to add further functionality, or is VISIBLE code locked behind blocks ?  Can a copy of the raw code be downloaded to a local device like my tablet for further study and manipulation ?
Thanks in advance for helping a really old newbie !

You'll have plenty of fun working with AI.

You won't really be able to convert App Inventor to Java. AI uses blocks language and you can get more info HERE.

AI2 is an open source project.  You can look at what is behind the scenes and blocks here:  http://appinventor.mit.edu/appinventor-sources/  

Perhaps you will enjoy perusing those files since you have some programming experience.