Best practices for wiring

Is there a section of the cab harness that is considered the 'best' or 'cleanest' place to tap into constant power and key-on power?

I'm sure I can find somewhere to hook in, but I am curious what the best method might be. Someone previously installed an aftermarket stereo harness, an didn't do the job as cleanly as they could have. The power is routed out under the heater controls, and the inline fuse is crammed halfway under the back of the dash. It's roughly a half hour to get the fuse out because of how badly it's located.

Anyway, thanks again for all the help. I'm going to make a whack at getting the electrical mess patched up tomorrow.