Thanks for contacting Syncfusion support.
Query: Can I load some data in memory and rest on demand based on the user scrolling or panning?
We have prepared a sample based on your requirement.
Query: How do I control what range is shown on the view area?
We can control the range of the view area by using the ActualRangeChanged event in the range axis. Event argument is with ActualMinimum, ActualMaximum, VisibleMinimum and VisibleMaximum properties. Based on the ActualMinimum, ActualMaximum property values, we can set the VisibleMinimum, VisibleMaximum property values to control the view range.