So I was curious about which containers were safe in the castle and you know what? I found out which ones are and guess what, they are all safe literally every container in the Main Hall where all the vampires are, are safe, the cathedral container (Lord Harkon's remains and the chest) are safe, hell even the containers in Valerica's study (the room with the soul cairn portal) are safe. Now for the displays, there are about seven weapon racks in the main hall, four in the armory, two in the room where all the vampires sleep and one in the lord's room as for the plaques in the armory they are also usable, take down the bows and weapons and you can place your own.

The castle comes with a lot of useful containers and displays, I don't even want to hear anything about it being dull or how you can't "trick out" the castle because technically you can, theres plenty of containers and the Castle doesn't even really need to be upgraded, as for the Dawnguard fort I haven't even bothered to try finding safe containers there because I already know its probably useless to even check.

Thank you very much for telling me this. I have asked the question, but no one answered. Now, I can move my thousands of items to castle Volkihar. Good think I used console on my PC before playing to make a ring that gives me a 500,000 carry weight! You know, just in case of this......

Yep ive had weapons displayed and used all the containers since the beta and everything is still there.