My personal opinion: claiming to be Satoshi and writing a book would be a good way to make a fortune. All you need is time and solid knowledge about bitcoin.
Mining needs a big investment in mining equipment, trading is risky, so why not write a book and use the name Satoshi as advertisement?
I've been around since before this forum, watching the bitcoin development. In my opinion people should stop idolising Satoshi whoever he/she/they might be. He was a good programmer but he was by no mean a God. If it wasn't for the help of the community Satoshi would never have been able to deploy bitcoin.