Getting from London to Windsor by bus (702 green line) is very convenient, even without taking the train. Photography is prohibited inside the church and castle. Seeing Queen Mary's Toy House reminded me of the inspiration for many miniature landscape designs in China. I personally think it's well worth a visit. Buying tickets is also very convenient. If you want to see the Changing of the Guard ceremony, enter the castle around 1 PM to find a good spot.