A bus for a day not to go to far, maybe one or two hours away, would cost between 800 to over 1000€ add that the tickets for 22 students and 2 to 4 adults...
We went to the castle of Chantilly last Friday (paid by the city) by foot. I had never been and it's exceptionally beautiful (we didn't do it all, just a few pieces as we had a guide who has arranged a tour on the subject I had asked for). I'll definitely be checking it more in depth and in the spring I'll do the royal stables and the horse museum. Chantilly is the horse capitale and the biggest training center in Europe (I guess I'm used to it by now but the first few days it smelled like horse shit in the whole city )
Pictures of what I drive by every day to go to work:
https://www.google.com/search?client=ms-android-xiaomi&sca_esv=17b6ad23b7736742&sxsrf=AE3TifNX5LAFhUxxvvFDVhPCfcYb-IXFQg:1761156398730&udm=2&fbs=AIIjpHx4nJjfGojPVHhEACUHPiMQ_pbg5bWizQs3A_kIenjtcl5m1cuBb92K2q0CMDvBK8EvRTOdQ9glAZGE0WeSSZzTiLTP2DQuRmTM1nLlvr86jO8Ph7sjMSzLMGfeZ5UqCULD-Y00eCCyIgQspiQb_lI18zBOHF0EEJdsS4Rh9XMs6BvITZPhS_OIyBi_5Ftqcg1sKF9d&q=chateau+de+chantilly&sa=X&ved=2ahUKEwjE76jssriQAxWEMvsDHeQvCeUQtKgLegQIEhAB&biw=392&bih=735&dpr=2.75