Hey Miller, some tips on exterior for ya... my dad taught me a quick and dirty "eyeball" method when I was like... 12, unfortunatly with the addition of "no-paint" windows, the system still gets fairly close today, 30 something years later.
1000 base for one story, 100 per hole (door/window)
1500 base for spilt, 100 per hole
2000 base for two story, 100 per hole, 150 per hole on second
Now adjust your prices slightly for mats and weird things like your free standing garage, sometimes my dad's quickie approach came out closer to everyone else than my own.......