As it turns out, the chamber of echoes is actually very easy and is more or less next to the entrance to the 3rd enclosing wall. The catch is that it's in the opposite direction from the one in which people normally tour the temple. So I didn't go straight there, but saved it for next to last on that level.
What I hadn't realize because all the photos I had ever seen were of the outside of Angkor Wat (and all the Amazing Race stuff had to do with the Chamber of Echoes) is that the walls are completely covered with amazing bas reliefs. I'm not a big fan of Asian art, actually. (In general, the only Hindu god I can consistently recognize is Ganesha, with his elephant head. The rest are just a jumble of guys with too many arms.) But the stonework at Angkor Wat is incredibly beautiful. The upper level (aka the second enclosure) with its apsara dancers in every corner is amazing. I ended up spending nearly 3 hours there.
I continued on to the South Gate of Angkor Thom, which is also striking. The Bayon was a bit less so, largely because the upper levels are too dark and not yet restored. And I was entirely unable to find a few of the bas reliefs I was looking for.
The rest of the central part of Angkor Thom was just okay. Leaving there, I had a lot of trouble finding my tuk-tuk driver. (I had apparently misunderstood where he was going to wait for me. Very frustrating.) At that point, it was close to 3 and I was too tired to absorb more, so opted to go back to the guest house and rest. I have a three day ticket so will continue tomorrow.