I will be traveling to Helsinki in late October or early November, but have heard great things about Estonia and I am thinking about including an overnight trip to Tallinn.

Is this realistic? My plane ticket is in and out of Helsinki, so I would need to return back. How long is the trip on the ferry? The cost?

Any hostels or inexpensive places to stay in Tallinn? Any sights that should not be missed?

And if anyone has some must sees in Helsinki, I would appreciate the advice.

Thanks!