Correct way to structure the Sync Framework DAL

I am creating a WPF application that needs to allow users to work in a temporary disconnected state and I am planning to use a local database cache.

My question is about my data access layer.

• Do you usually create the entire DAL to point to the cache or both and create a switch mechanism?

• Is Entity a good way to do my DAL vs cache?

• I'm used to L2S, but my understanding is that I can't use this against SQLCE, right?

Thanks!

PS: Any good resources for using Sync, Linq, and WPF ALL TOGETHER ? Tutorials, videos, etc.