Is there any way, aside from looking at the rulers and measuring by eyesight, to find the precise distance between one guide line and another?
Even Quicker way to measure distance between two guides is to use the marquee tool. If you are on photoshop CS6 - Create a Marquee rectangle snapping from one point to the another. CS6 shows a tooltip with Width and height while u create the box. If on lower than CS6, you would get the values in the info Dialog - (CMD + fn + F8) or (Ctrl + F8)