Its hard to find blueprints or track layouts, so the best way is to use pictures, or memorize the layout yourself. You also need the rides stats so you can make it the correct height and stuff. I made a replica of Hulk using RCT and its almost as accurate you can get in RCT. I'd really like to attach a screenshot of it or the file itself, but we can't!
If you want a good site with lots of coaster pictures go to www.rcdb.com . Also if you want to build a coaster at Cedar Point, their website has a few track layout pictures, plus POV videos.