Nice thread, I went through the same process a few years back.
I picked up most of the bricks in a large lot of lego so i had all the hard to find bricks, and i purchased brand new bricks where i could. the castle turned out really nice. I also had a problem with the original stickers so i scanned in the old ones and redrew them in Illustrator.
Once i had finshed the 375 set, I started on making the castles from the 6000 ideas book. below are the photos i have of the smaller castle
About a year after that set i finished the big castle, i have not taken any photos of it yet, if i get around to it i will post them up here.
I had always wanted the 375 set and i must have studied the 6000 book for years as a young child. It is really rewarding to have something that you wanted so much as a kid.