Hello jksimba
I wonder why you wanted to visit Liechtenstein. It would not be my first destination to visit, to be honest. The castle cannot be visited, and you will not really notice that you are in Liechtenstein, apart from the black car plates.
You could travel:
Geneva - Olten - Zürich HB - St. Gallen - Sargans- Vaduz - Sargans - St. Gallen - Luzern - Interlaken Ost - Montreux - Lausanne - Geneva or Interlaken Ost - Bern - Lausanne - Geneva
Geneva - Olten - Zürich HB - St. Gallen - St. Margrethen - Vaduz - Sargans - Chur - Brig - Montreux - Lausanne - Geneva
Kind regards,
Roland