nice one Sam. A Neck pickup will make this a unique Jr build and give you heaps more sounds.
Has the person thats done the routing drilled a hole from neck to bridge pup ? You will need a really long drill bit to do this if he hasn't. You might have to enlarge the hole from bridge pup cavity to control cavity to fit the extra wires. Are the pickups just a hot and earth wire or 4 wires (splittable) ?
Also you will need a switch so you may have to ditch the tone pot or make the cavity bigger for a switch?

Looking at the distance between the 2 holes you may fit a switch between them