Colder'n - a whore's heart (or well digger's ass)(or a cast iron
          toilet seat)
Hotter'n - Kelsie's nuts (or a two dollar pistol)

Bad aim or eyesight: He couldn't hit water if he fell out of a boat!

If brains wuz dynamite, you couldn't blow yer nose!

Meaning indeterminate: "Fixin" - as in, "I'm fixin to do (blank)."
Does it mean planning to do it, thinking about planning to do it, just thinking it over generally or....?

My dad used to refer to "shade tree mechanics," like the fellow a friend ran into in rural Georgia when his Mazda rotary engine gave up the ghost. He was towed into a little crossroads town by a local mechanic. When he looked under the hood, he threw up his hands and said, "Hell's fire, mister; I cain't fix this thang - it ain't got no pistons in it!"