One page and auto link
It sounds like it will depend somewhat on your set up. If you're on Drupal, you could have a look into using webform civicrm which would be able to handle all of the above (creating the contacts, relationships, and membership). You could also do clever things like populate the name of the Household based on the Last name value entered for one of your contacts.

I'm not as familiar with the other CMS integrations but hopefully someone more versed in Wordpress or Joomla can chime in if you're using one of those.