Hi Tony,

for single player the beta_8 version is best.
What do you mean by separate CD disks?
It's good to have a separate copy of MTW/VI, that's true.
The maps are probably for MP, which ones do you mean?
The additional castles are nice to have, follow Puzz3D instructions on how to install them. (first post in beta_8 thread)
You can ignore the stats changes for now.
Have Fun!