These castles are without a doubt some of the most beautiful castles I have ever visited. This summer, I visited Neuschwanstein for the second time, and Linderhof and Herrenchiemsee for the first time. It's important to book tickets in advance (esp. for Neuschwanstein) and to get there in time as the tours all start right on time. The tour guides we had for all three castles were very good.

In Linderhof, I would also recommend walking to the smaller buildings in the garden as they are simply stunning (although some are replicas and many are not located where they were orginally placed due to various reasons). The climb back from the Hunting Lodge to the Castle is quite challenging though, so make sure to wear good shoes and take enough time so that you don't have to hurry back for the guided tour. The Moroccan and Moorish houses are especially stunning, but I was completely taken by surprise by the beauty of the Hunting Lodge.

Herrenchiemsee is beautiful as well. The ferry ride to get to the island is smooth (so no fear for sea sickness) and goes frequently. Alternatively, you can choose for a longer tour that will also bring you to the neighbouring island. After the ferry, you can opt for a carriage ride to take you to the castle or you can walk there. There are a lot of mosquitoes in the forest you need to cross, so bringing bug repellent is a good idea (can also be bought at the castle).  

Neuschwanstein remains my favourite of the three castles. The climb to get there is quite steep, though. You can also go by horse carriage, but that will only bring you 3/4ths of the way. The remaining part of the walk is rather challenging too. This castle clearly gets the most visitors, so I would recommend going early so that you don't have to wait too long to get a carriage if you want/need one. 

Unfortunately, we were not able to visit Königshaus. I would have loved to visit that one as well as it seems stunning, but it can only be reached by hiking for a couple of mountains up a rather steep mountain and that was unfortunately not an option. You can buy guide books with lots of pictures in Linderhof though.