I bashed a Beacon Hill to be the part of a castle. I don't recall the main structure being very difficult. I can't speak to the windows and trim, however, because I didn't did straighten the wall in the entry hall. This made the big room on the first floor larger.
I have personally found the bigger houses like the Beacon Hill and the Garfield much easier than the smaller houses. I had the most trouble with the Orchid, which is ironically a house that many people start with.