I figured I'd take some pics and post instructions on how to remove the upper playfield on WWFRR in case anyone needs it. The tools you'll need are:
-Phillips head screwdriver (large and small tip)
-5/32 Allen wrench
-9/64 Allen wrench
-11/32 small wrench
-Screwdriver with socket attachments (1/4, 5/16, 11/32)

First you'll need to remove the left and right wire ramps. Next remove all the plastic covers on the upper playfield.. You can leave the wires attached and just set them aside. Below you'll see most of the screws/bolts that need to be removed. Don't forget about the plastic cover at the very back of the playfield. Theres a clip that attaches is to the left ramp.

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Now that the plastics are off you'll see the nuts holding the upper playfield in place. You can loosen them but I would recommend leaving one attach to keep it in place while you set the playfield upright to remove the flippers/diverters and wire harnesses.

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Tip the whole playfield upright and loosen the flipper bats and diverters. Below you will see where they are secured. A 5/32 allen wrench is needed for the flippers and a 9/64 allen wrench is needed for the diverters. Also unplug the two wire harnesses for the upper playfield.

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Once these are loosened carefully pull the flippers and diverters from the top up through the upper playfield. Do this slowly to make sure they don't catch on any wires.

Set the playfield horizontal again and remove the VUK ramp. This one is a little tricky and will probably require a 11/32 wrench. There are two nuts that secure this ramp and one is under the upper playfield. At this point you can remove all the nuts keeping the upper playfield attached and wiggle it to make some space so you can remove the VUK ramp. Once that's out of the way, the upper playfield should pull right up and off. Be careful that the left plastic ramp doesn't get caught on it.

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Reassembly is basically the reverse process. An important thing to remember is to remove any gremlins from your machine before you put it back together.

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Don't forget to get the VUK ramp secured before tightening down the upper playfield. Once the playfield is in place it is impossible to get the VUK ramp fastened and you'll have to loosen the whole upper playfield to get at it(speaking from experience). Also there's a wire harness that has gotten wedged in between the drop targets and the plywood in me before. Make sure that is out of the way.

And that should be it. Reinstall all the ramps and plastic covers.

*Bonus TIP*

I'm not sure if all the data east games used these short metal guides that go underneath the playfield but they're terrible on my WWFRR. They barely protect anything and the guides end up digging into the plywood.

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ditch those crappy brackets and replace them with some stern edge slide brackets (535-5988-01 ). They use the existing screw holes and add much more protection, making it easier and less damaging to slide the playfield around. I drilled a small pilot hole and added a #4 1/2" screw and it works much better.

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you can find them at pinballlife and marcospecialties. less than $6 for both brackets!
http://www.pinballlife.com/index.php?p=product&id=2833
http://www.marcospecialties.com/pinball-parts/535-5988-01

I wonder if there's a wire or harness sticking in the lane

The bulbs that light the belt inserts are 555, and there's 3 of them. The two other bulbs are 44/47. I recommend non ghosting frosted leds for the inserts. There will be faint ghosting if you get regular leds.