Some hints on what to look through

I've just purchased the engine and have spent the evening reading through various scripting resources and such, but it looks like I am definitely going to have to break into the C++ code to do what I want..

So, all I am looking for is a few hints on where to look - there's a hell of a lot of code here.

One of the things I want to do is free the camera from its player centric view - I want it to be an "isometric" style adjustable camera. What classes should I be looking at?

The other thing - I am going to have buildings on my map, but since the camera will no longer be first person, I am thinking that using the BSP/Portal version of the buildings will basically break, as I want to cutaway/transparent-ize the walls so you can see characters in the buildings (think Fallout)

Obviously some people must be doing similar things, as I've read people talking about rpgs, strategy games, etc. Most of the scripting and such seems very straightforward, I just have to figure out what's involved to break the engine out of it's First-Person sort of bent.

Cheers,
Jason