Jabez - all good suggestions, but I think Fritch doesn't much like the museum experience and prefers wandering among the ruins as well as just being outside to appreciate the overall architecture. Castel Sant'Angelo I found very interesting and wouldn't be so quick to dismiss it since he's done areas close to the Vatican before and wants to do different things now. It does dovetail with what he has already seen, though - just my two cents, not holding myself out as an expert by any means.

Sandra