If you don't care about comments and PIs outside root element, all you
need is to move reader to content and read outer XML:

r.MoveToContent();
Console.WriteLine(r.ReadOuterXml());

if you do care about that stuff at roto level, then you can use
something lik ethis:

StringWriter sw = new StringWriter();
XmlTextWriter w = new XmlTextWriter(sw);
while (r.Read())
    w.WriteNode(r, false);
w.Close();
r.Close();
Console.WriteLine(sw.ToString());