I'm planning a trip to Mérida to explore its Roman sites. Can you tell me which major Roman archaeological sites are accessible with a single ticket, their general opening hours for both summer and winter seasons, the best ways to get around the city to visit them, and if there's an official mobile app to help with navigation?
Navigate to the 'What To See' section under 'Plan Your Visit' to identify key Roman sites. Navigate to the 'Fees and Hours' section under 'Plan Your Visit' to find general opening hours and confirm sites accessible with a single ticket. Navigate to the 'Moving About' section under 'Practical Guide' to understand transportation options. Navigate to the 'Mérida Guide App' section under 'Practical Guide' to check for a mobile application and its purpose. Synthesize information on key Roman sites, general opening hours, recommended transportation, and app availability.
List the Roman sites accessible with the 'Entire Set' historical-archaeological ticket (Roman Theatre and Amphitheatre, Roman Circus, Alcazaba, Morería Archaeological Site, Crypt of the Basilica of Santa Eulalia, House of Mithraeum and Columbarium). State the general opening hours for April 1 to September 30 (summer season) and October 1 to March 31 (winter season), including the exception for Morería. Describe the recommended method(s) for moving about the city, mentioning both walking and public transport. Confirm the availability of the 'Visⓘt Mérida' official app and explain its purpose. Provide a concise summary integrating all the requested information.