This is very easy to do with the tools listed in the first post.
- Rip the DVD with DVD decrypter
- Open the files with DVD shrink
- Select "reauthor" in the top bar
- Drag the movie over to the window on the left.
4b. Set the compression to "none"
- Right click on the "title 1" or whatever the main film is.
- Select "define start/end points"
- A window will pop up that allows you to choose start and end chapters (or anywhere within a chapter).
- Start at chapter 1, and choose end chapter about half way thru the film (there is a preview window to help you).
- Click OK
- Check the green bar at the top of DVD Shrink. If it is green you are OK, otherwise pick a different chapter to end on.
- Click backup and save the files to a folder (or burn the directly if you wish).
- Repeat the steps above, but this time choose the start point to be the chapter after the one you ended with last time. For example if you backed up chapters 1-17 on the first disc, start with chapter 18 and go thru the end on the second disc.
- Click backup again and save the files (or burn them directly).
I hope this is enough. I don't have DVD shink on this computers so I can't verify that everything I typed is exact but it should be close.
You can also do this with all of the menus and special features (provided that you keep them on the first disc), and just back up the remainder of the film on the second disc. The chapter select menu won't function correctly, because it wont be able to find chapters located on the second disc.