I did forget to mention that The Door VFD harness will be more than long enough to reach from your power dist board to inside the topper unless you are mounting it on a 31" high Round top or such top box
Since I change top boxes from 9" to Round Top. I made a modification to harness
I removed the 13V power and ground from the 10 pin molex.
Since the 4 pin connectors on the power dist board provide 25V, 13V, A Ground, B Ground, I installed a 4 pin connector on them
then used a male and female 6 pin mini-fit jr for the netplex portion of the wiring
You will need to extend your candle harness and a ground wire.
a spare candle can donate the correct wiring and connector.