I tried a lot of things with logintoboggan but the unauthenticaed role makes it diffecult for other modules to make well. So if you try to establish this with logintoboggan you are implicied chosing for modules which are only compatible with the adjustment of the login system. Something I do not prefer.
I solved it with the following modules:
Email_registration fo the username is not needed anymore
GenPas for generating a auto password and direct login
Persistent login for login in for a long time
User email verification for verify the email
nocurrent_pass for remove password edit’s profile
email_confirm when user changes email
When a anonymous gets on the site reqistrating is posssible with only email. With a rule you give the person a role. After that you can do what you like. If the person does not have a role yet and clicks on the link for premium content, you just append the unique id to the registration url and after registration a redirect can pick this up, the person is then verified with a first pre member role.
You send all pre member roles an email with user email verification. If this is verified u can use a rule to upgrade the role. You now have a full registrated process without have the disadvanced of logintobboggan concept and in line with tha fact that no passwords are send by email.