What are the best strategies/practices for Rails upgradation from 2.3.11 to 4.0.0?

I would like to upgrade one of my application from rails -2.3.11 to 4.0.0. Before going to do anything, I just need plan for it and my application not that
much of big size but got some 6/7 plugins and 5/6 gems.

Existed    : Ruby 1.8.7 + Rails 2.3.11
  Expected : Ruby 2.0.0 + Rails 4.0.0

   For this, I have plan as in two ways like below,
   1).Multi-step process : First need to upgrade app from rails 2.* to 3.* and then
      do upgrade from rails 3.* to 4.0.0
   2).Create new application from rails - 4.0.0 and rebuild old application all features as we have already css, layouts...

   I hope both strategies will take same time.

 Any how, I need some inputs from you all. So please share your thoughts/comments.

     Thanks in advance.

Step zero is to make sure that you have full test coverage so that you
can be confident the app continues to work correctly.


Step zero point one is to review your 6/7 plugins and 5/6 gems and ensure they’ve been moved forward to your final target.