Flip the LiPoly backpack charger over and look at the back. There's a little silvery patch. Take your soldering iron and bridge the two pads here -- this will make your staff charge a lot faster.
Find the long wire from the switch. Measure it out to a good length and then solder this into the inner power switch hole on the LiPoly Backpack.
Solder a short yellow wire into the 5v pad, and a short black wire into the G pad on the LiPoly backpack.
Place the LiPoly backpack on the back of the Pro Trinket, making sure it doesn't block pin 3 or 13. Use a big dollop of hot glue to glue it in place, making sure the glue insulates the back of the backpack from shorting out on the back of the Pro Trinket.
Just a few more wires to hook up!
Connect the yellow wire from 5v on the LiPoly Backpack to the BUS pin on the Pro Trinket.
Connect the black wire from G on the LiPoly Backpack to the - pad on the BACK of the Pro Trinket.
Twist together a long (2 ft) and a short (3 in) red wire, and solder both into the 5V pin on the Pro Trinket.
Twist together a long (2 ft) and a short (3 in) black wire, and solder both into the G pin on the Pro Trinket.
Solder a short (3in) green wire into the 3 pin on the Pro Trinket. These three short wires will later attach to the IR sensor.
The long wires will go to the LEDs and power switch.
Take the long black wire and run it down to the middle of the staff. Find your twisted pair of black wires coming from the LEDs, and splice it in.
Red is a tiny bit trickier. It's the same idea, but you need to incoporate the other wire coming from the switch as well.
Run the long red wire down toward the battery until you find the loose wire coming from the on/off switch and twist these two together. Slide some heat shrink on and splice this pair together with the red pair coming from the LEDs.
Attach the green (data) pin coming from the LEDs near the Pro Trinket to pin 11. Attach the yellow (clock) wire to pin 13.
Trim the leads on the IR sensor down to about half their length.
Strip about 1/2 inch (yes, that's a lot!) of shielding from each of the three remaining wires coming from the Pro Trinket and slip a large piece of heat shrink onto each wire.
As you're looking at the sensor with the bump facing you and the legs down, coil the green wire (to pin 3) around the left leg, the black wire (to ground) around the center leg, and the red wire (to 5v) around the right leg. Solder and secure with heat shrink.
Be sure you get this right! This sensor will quietly break if you mix up the wires so double check that you're doing it right.
Glue the IR sensor to the side of the dowel with no LEDs and make sure it'll fit nicely inside the tube, without being covered by the cap.
The battery wires are very straightforward. ONE AT A TIME, carefully cut each battery wire, and splice in enough wire to extend the connector to the LiPoly backpack so that it plugs in happily. (Don't ever cut both battery wires at once, in case your cutter accidentally causes a battery short)
Plug that bad boy in and press the switch to make the lights come on! Grab the remote and press some buttons to be sure it's all responding.
Once you're sure everything is working, take a minute to manage your wires so they're comfortably running down the sides of the dowel, and not blocking the LEDs or bunching up anywhere.
Finish up by sliding everything into the tube -- this works best if you start with the Pro Trinket end since the switch is a nice tight fit.