Day-trip castle math
Best castle bases: cities where you can choose between 3+ castle visits without overnight stays. The Bavarian Alps, Scotland, Czechia, Loire Valley each have multiple castles within an hour of an anchor city.
Munich
Munich the Bavaria castle hub. Neuschwanstein + Hohenschwangau (2h drive south, day-trip with tour bus), Linderhof, Herrenchiemsee, Nymphenburg in city. Dachau also day-trip distance for darker history. Altstadt base.
Edinburgh
Edinburgh Edinburgh Castle in city. Stirling Castle (1h), Linlithgow Palace (45 min), Doune Castle (1h, Outlander/Monty Python), Falkland Palace. All connected by ScotRail or 1-day tour buses.
Vienna
Vienna Schönbrunn and Hofburg in city; Belvedere Palace; Liechtenstein Garden Palace. Day-trip: Bratislava Castle (1h by train), Burg Forchtenstein, Heiligenkreuz Abbey.
Prague
Prague Prague Castle in city (largest ancient castle in the world by area). Day-trips: Karlštejn (40 min), Konopiště, Český Šternberk. Czech "castle Sunday" tradition for locals — visit several in a day.
Lisbon
Lisbon Castelo de São Jorge in city. Sintra cluster day-trip — Pena Palace (the iconic colorful one), Quinta da Regaleira, Castle of the Moors, all in one Sintra day. Belém Tower also Lisbon-perimeter.
Tours / Loire Valley
Tours is the obvious Loire base — Chambord, Chenonceau, Amboise, Villandry, Blois all within 60–90 min by car. France's deepest castle cluster.
Strategy
Pre-book Neuschwanstein 2+ months ahead for summer. Loire requires car or organized tour (public transit thin between châteaux). Combination tickets save 25–40%.