That 'crest the hill inverted' trick is insane... They do it because following the contour of the hill while flying right sire up would result in too many negative g's. By flipping inverted, the g-force is now 'down' (relative to the pilot) and they can pull a lot harder (since the body is much better at dealing with g-foreces in that direction).
Probably one of my greatest memories from NTC is being on a hill, and having an A-10 crest the hill, inverted, and then roll over as it continues down the other side on its way to attack a column of OPFOR armor. F-16s and F-18s would just zip right by and be gone in a second. The A-10s would lazily swing back and forth as they worked their way down the valley.