The purpose of Green mode is "everything auto, let the camera decide".
Many of the options are unavailable in Green mode - just switch to Green and look through the menu. You can't even switch the top LCD backlight off!
RAW is for people that want to make their own decisions about what happens to their image. As Liz said, use P if you want a good compromise between 'everything auto' and 'I know enough to make my own decisions".
I can't see any benefit of PEF any more. On the K10D, PEFs were much smaller than DNGs, and I used them exclusively. K-5 PEFs can't be read by Picasa or any version of ACR compatible with CS3, and there's no file-size benefit. I've switched to DNG with the K-5.
The manual is thick, but the pages are small. It's no harder to read than others, so go to it