Plan to hand wash my engine compartment tomorrow.
 

Watched Junkman's video on washing the engine...check!

Question is: Besides the alternator and air filters is there anything else I should cover?

I use a very diluted concentration of Adam's All Purpose Cleaner for the engine bay. When I have the time, I clean my aftermarket intake tubes (for stock I would wipe down the tubes and the filter housing), radiator shroud, strut bar, engine cover, and all of the plastic cowls and covers for the battery and brake/clutch fluid compartments.

I use simple green, spray it on, let it sit, scrub where needed or I can get to, rinse off for tooooooo long