1) You can also make use of the Bookmarks feature and menu for this. What you do is get in the habit of setting a book mark when you're ready to switch books. Then hold down the Mark button for 5 seconds to go straight to the "all bookmarks" menu (you can also just click the Menu button once if that menu was the last one you visited) which will show you your list of bookmarks. Select the bookmark in the book you want to switch to and bam, you're there.
Note that this doesn't work so well if you like to set a bunch of bookmarks in the same book for whatever reason, the menu gets too cluttered to be useful that way.
However, each book's title menu will have a "continue reading" option, so you can always get back to your last page that way, as athlonkmf suggested in the first place.
2) general rule of thumb is that if you can read a paper book by a given light, you can read the Reader almost as well by the same light.
