Read only version of node form for anonymous users?
can anyone suggest a way to preview the form?


The no code way would be to use screen shots (images). 

Alternatively, you could check if the user is logged, it they are not then unset the submit button via a hook_form_alter.


  prevent someone from circumventing it by submitting the form manually


Better yet, if user is anonymous, you alter the callback function of the submit button by unsetting the existing one and adding a new custom callback.