Designing Wireless for a 650 Year Old Castle | PRG 26

I was tasked to design the Wi-Fi in an over 650 year old castle. Of course you can imagine the obstacles like protection of historical buildings and walls so thick you could live in them.

Besides the obvious "AP in every room you need Wi-Fi", I was wondering if I could do an accurate model for a predictive design, without doing APoS in the whole building.