Redirect to custom URL while logging in user through Webform
Another current question here inspired me for this short solution within your hook_webform_submission_insert():

 // Create user account.
 $my_user = user_save(NULL, $user_data);
 // Whether the user account was created successfully.
 if (!empty($my_user-&gt;uid)) {
   global $user;
   $user = $my_user;
   user_login_finalize($user_data);
   // Do the redirect here.
   drupal_goto('target_uri');
 }
 else {
   // User account could not be created. So do some error handling.
 }