Q:

Rails3 Devise custom routing for confirmable module

I am trying to route a user to a custom welcome page after they confirm their account via devise's confirmable.  The custom page is located at /districts/setup/, reachable by  districts_setup_path. 
To do this I added the custom route,

  devise_for :users, :controllers => { :registrations => 'registrations', :confirmations => 'confirmations' }

and created my own controller.  Then I had to overload the confirmations_controller.rb and now have:
(app/controllers/confirmations_controller.rb)

class ConfirmationsController | Devise::ConfirmationsController

  # GET /resource/confirmation?confirmation_token=abcdef
  def show
    self.resource = resource_class.confirm_by_token(params[:confirmation_token])

    if resource.errors.empty? 
      set_flash_message(:notice, :confirmed) if is_navigational_format? 
      sign_in(resource_name, resource)
      redirect_to districts_setup_path
    else
      render_with_scope :new
      # not:
      # respond_with_navigational(resource.errors, :status => :unprocessable_entity){
    end
  end
end

This works well, but I am nervous that I am not doing this in the mostideal and robust way.  In particular, I just deleted the respond_with_navigational( ... ) lines which I really don't understand. 
I am hoping to write this all up in a how-to for the Devise wiki, and am just looking for feedback being fairly new to rails and even newer to Devise/engines/warden. 

A:

Taking a look on Devise's ConfirmationsController you can spot the protected method after_confirmation_path_for(resource_name, resource).  Overriding it (rather than the whole action) will produce the same results with less effort. 
Generally speaking, there is no problem with overriding Devise's controller since they represent the default behavior which doesn't always suit the application needs.  That being said you must take a few things before overriding Devise's code:

Devise is not just another component of the system - it handles user authentication, which is a very sensitive issue.  Make sure you don't break anything important before you commit it.  You can do so by forking the Devise project from github, making your changes, and running the tests. 
As you make changes to devise and override its code, it will become harder to  upgrade to newer version, which might be incompatible with your changes. 
If you do decide to make a change, look for the smallest change possible to achieve your goal.  In most of the cases Devise's team has already foreseen the need for customization in certain places and left methods (like the one above) which are dedicated just for it.  Again, going over the file's code on Devise's GitHub would give you a good idea as for what is the best way to customize its behavior to your needs. 