you dont need to put an external 5V onto the BOB, you can just send the clock and direction from the bob to the driver, and as long as the clock and direction is close to the 5V, it will be fine.

All i need to know is if the clock and direction is coming from the PC and is high enough for the optos to operate.

Use 3 AA type (1.5V) batteries in series to get 4.5V and connect the negative end to the Pul- and tap the positive end on the pul +.
This will cause the motor to step one increment and while you may not see it moving, you will hear it.
You can also put some tape on the motor shaft so you can see the motion.