How would I clone a part to a random position inside another part?

Okay, so this one'll need a liiiittle bit of work: You want your position to be within the part, so assuming they're not meshparts, unions, or anything else that would change the meaning of "inside" it, you may want to do something similar to this:

--NOTE: Untested
local PartA,PartB = --...
local MaxDisplacement=(PartA.Size-PartB.Size)/2
PartB.CFrame=PartA.CFrame * CFrame.new( --Goto A's CFrame, and displace by random xyz
    -MaxDisplacement.X+math.random()*MaxDisplacement.X*2,
    -MaxDisplacement.Y+math.random()*MaxDisplacement.Y*2,
    -MaxDisplacement.Z+math.random()*MaxDisplacement.Z*2
)