This is an old response that I started but never sent till now so I'll respond to any other posts after this one:
Thank you PlaymoMan, Tahra and Tiermann! Tahra, I agree - I've always loved the ox cart! Tiermann, the problem is that - as far as I recall - those doors won't fit onto the castle if you want to keep the drawbridge also, which I do. Bummer. Any ways around that that you know of?? Flatcat, that's good to know - I must have gotten a bad egg. You practically look at it the wrong way and it falls apart. I love everything about the rock castle besides that though. I wonder if these latest castles hold together even better, or if they're about the same, do you know?