And if you have trouble getting your double taps to be recognized, you can usually Ctrl tap and choose "Open". (Astropad has a Ctrl key button, press on it while you tap).
There's no auto keyboard yet but you can get to the OS X keyboard viewer. Here's a neat trick: Go to System Preferences, Keyboard, Input sources. Make sure "Show input menu in menu bar" is checked. Now add a 2nd keyboard. For example, I chose U.S. or U.S. Extended. Now the icon in the menu bar is your country's flag. Tap on that, then Show Keyboard Viewer... and there's an onscreen keyboard. It's a little clumsy but it works.