Okay, let's take a crack at this:<br/><br/>Site #1<br/>120 kilometers, 78 degrees.  An abandoned farmstead that could be converted into an underground facility easily.  Area around is plains.<br/><br/>Site #2<br/>289 kilometers, 184 degrees.  Cliff face in a small canyon, approachable from only one direction.  Directly ahead.<br/><br/>Site #3<br/>396 kilometers, 85 degrees.  Rolling hills, very isolated.<br/><br/>Site #4<br/>583 kilometers, 218 degress.  Dense forest, anyone approaching would be easily spotted unless moving very slowly.