You should be able to handle all that within the routes.rb file. Wrap all your current routes in scope; for instance.
scope "/context_root" do
resources :controller
resources :another_controller
match 'welcome/', :to => "welcome#index"
root :to => "welcome#index"
end
You can then verify your routing via the rake routes
they should show your routes accordingly, including your context root(relative_url_root)