Museums outside Tallinn reward the effort it takes to reach them — from a 13th-century bishop's castle in Haapsalu to Estonia's largest museum in Tartu. None of these are a quick tram ride from Old Town. The closest is about ninety minutes by car, and the furthest sits almost on the Russian border. If you have a spare half-day or a rental car, though, they show a side of Estonia the capital doesn't. At a glance: Rakvere Order Castle — Half day · ~1.5h drive east Haapsalu Episcopal Castle — Half day · ~1.5h drive west Tartu (ERM + Sports Museum) — Full day · ~2–2.5h by bus or train Kalevipoeg M…