I was exploring the keep and personally I find one particular thing very strange about it:
Why is the measter living in probably the worst location in the keep - the attic - firstly it gives an impression of a makeshift shed, with no heating/benefits of stone walls.
Remember Measters were a highly educated people of prestige, often from noble houses and having one was a prestigious thing for the lord. Thus I would recommend relocating it to the keep proper - maybe into one of the fancier rooms, or even swap the guard living quarters with the measters, as right now you have lowborn people living in a better condition then presumably a person of a highborn heritage. Another option would be to get rid of the rookery & measter all together as to quote awoiaf wiki: (taken from DWD chapter 37)
if a lord does not have a maester in his service, he is seen as unimportant
Cheers,
_Simbaa