Speaking broadly, the village huts are all pretty shabby, like you would expect to see in medieval Iceland, some of the Motte and Bailey castles are basically picket fences around a hut, and even the "good" Castle where King Edward lives seems to be a ruin (I suspect this is because they filmed in a ruin). Some of the interior scenes actually seemed a bit incongruous, because the exterior shots would suggest that there aren't any building's in Scotland big enough for a man to stand up straight inside.
Is that a fair portrayal of England/Scotland in the 1200s, or did the film overplay the squalor?
As far as the average rural Highland Scot at that time was concerned, the medieval Icelandic house was very similar. Turf or stone walls covered with a thatch of heather with an open hearth at one end, the smoke from which perculated through the thatch and also kept out the flying insects.
Wooden partitions were used for privacy, not normally a full partition, chest height would be enough.
http://www.highlandfolk.com/kingussie-founder.php
Whether the same applied to Lowland Scots I'm not sure. Note that William Wallace and Robert de Brus were fairly well-off lowlanders and would have lived in better houses than the huts shown in the movie.
I am not an architectural historian, but I know we have some in /r/architecture. Depending on the response you receive here it might be helpful to x-post this question there.
Trim Castle in Trim, County Meath, Ireland is where they did the filming -
http://cdn2.vtourist.com/4/6869748-Braveheart_the_movie_Trim.jpg?version=2
You can take a tour of the castle, at least you could recently, back in 97 there were no tours so they may have stopped them again
If I remember correctly, some scenes featuring King Edward are meant to be in London, and if it's the 1200's, the castles Edward would have been in would probably have been Windsor, Warwick or the Tower of London.
Any of these would: A) Not be a small, dark, dank hole as depicted in the film (at least not in the great hall). B) Not be plain and barren stone, but rather covered in tapestries, paintings, torches, etc.
