You can check the "Various Data Sources"
SDK example. Basically, the approach for populating data from the server is the same as with MS DataGrid control or any other items control. There is nothing specifically related to RadGridView.
As to the data operations, they will work similarly no matter if your data is in memory or not.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.