You could use the MIN/MAX calculations/formulas in read-only fields.

You'll need a more complex formula or field rules or something if you don't want it to show a default minimum date when the table doesn't have values, but the following will get you started.

=MIN(Table.Start_Date)

=MAX(Table.Start_Date)

Just replace the variables with the appropriate ones for your form. MIN/MAX work with lists/arrays of values, and since a table column is already a collection you can plug it right in.

MIN/MAX only work with numeric values, but as long as you're using actual date fields it can handle the value properly since dates have an underlying numeric value.