You can get the RC0 offline docs here. Using this file you don't have to deal with the delay of online browsing and when you do a search, you are only searching in Silverlight content.
One tip: If you are running Vista you might run into an issue when you open the CHM (the CHM will open but nothing will be shown in the pages). This is a security "feature" of Vista and you can work around it like this:
- Right-click the CHM file, and then click "Properties".
- Click "Unblock".
- Double-click the .chm file to open the file.
Let me know if you have issues downloading and using it.