Well here's the question......since light progresses out in all three dimensions from its origen, does it then not require a fourth dimension for it's crests and troughs?

Light waves are not a displacement waves such as water waves. They are Electro-magnetic waves. The "crest" of the light wave is not a place of maximal displacement, it is a place of maximal electric and magnetic field strength. The trough is not a place of minimal displacement, it is a place of minimal electric and magnetic field strength. Three spatial dimensions and one time are plenty for containing electromagnetic waves.