I'm pretty versed in the world of detailing, but after a bad experience with my first truck, I have only done my Silverado once.

How warm/cool does the vehicle need to be? Normally I would wash my cars first thing in the morning while they are cool, but now that we live in an apartment I must drive to my mother's house to clean our cars (20-30 min drive) how long should the vehicle sit before I try to clean the engine?

I have a 50/50 mix of APC I use for everything, on my wife's car it should work fine as I am mainly trying to get dirt that stuck to the crap the dealer put on it (i really should have cleaned that crap off as soon as we got it)
But on my truck there is some built up grease around the intake and valve covers. Will the APC work there or should I get a heavy duty product?

How long should the APC sit?

 

I go buy a whole spray bottle of simple green, do not dilute it, take it to the car wash and use that whole bottle of simple green...drench the engine bay, let it sit for 5 minutes, and blast it all off. Avoid the coil packs and your intake (if you have an open element filter) and when you get it all off dry it off with a towel and use whatever shine you like to shine up the plastics and roll with it