I had no problems setting up and building PBRT. The instructions were straight forward and I was able to build the project easily (practically no changes to any files, just followed the instructions) using Visual Studio Express 2005. I got a lot of warnings but I'm sure those are just typecasting and versioning issues.
At first I was a little confused because I didn't know whether or not I was supposed to manipulate certain values of the light sources... so I was stuck trying to mimic the first configuration only by modifying the light position. However when I tweaked the other values I was able to create the required image. It took me a while to get the geometry straight in my head for rotation and translation (like remembering that rotation and translation are order dependant). Also dealing with area lights was interesting when the disk itself showed up in the scene because I didn't rotate it correctly.
As for the speed up, it wasn't really an issue for the first 3 configurations. The programs didn't take more than 5 seconds to render with the default configuration. In order to speed up the fourth configuration (and to make sure my lighting was on the right track), I only rendered with one light visible at a time. But in order to gain a better understanding of speeding up the rendering process I played around with the image resolution and the area light source sample numbers to try to get a faster speedup during the test process. I see how this will be extremely useful in future projects when lights and objects require lots of fine tuning to position and parameterize correctly.
Note: I also had to turn the images into 16 bit resolution in order for photoshop to allow me to save them as .png files. If this is unacceptable please let me know. Thanks!
I had a lot of fun messing around with the translation and rotation settings (both in camera space and world (?) space). For example, I wrote the fourth configuration both by modifying the camera's lookAt function and by modifying the objects and lights in the scene to create the same rotation (simple, but good practice). Playing with the colors (kd for example) was also interesting. I'll probably try rendering some interesting new scenes in the near future. I need to read more of the book to understand some of the other settings I could play with.