I'm continuing working, at a snail's pace. That's the pace that is allowed when I work only by myself, and only with materials on hand. Over the past week or two, I made sure that all the wiring in the riser was in place and the conduits were set (though it occurs to me now that I should have made sure the PVC pipe joints were all glued - I hope none come apart). Since I had plenty of 3/4" T&G subfloor on hand, I have made use of that.
The riser is decked with the first of three layers. I'll probably be better if I have help for the next two layers, as they will get green glue. The outer two joist bays are filled with sand - and you can immediately tell the difference in sound when you walk on it. The center 6 feet or so is all open (joists hang from rim) and have a single layer of R13 insulation on hangers. In theory, I can cut open some vents for bass trapping if I need to.
You can see in this picture that I have LV wires protruding out the front - one HDMI, two cat5e, and one mic cable. You can also see an additional conduit for future wires (to the left in the image). The step lights are wired and in place, and the outlets for power (mostly for the seats) are roughed in, both in the front face of the riser and in the deck for under the second row. In the corners, you can see the rough in for more power - those two outlets are on the same 20Amp circuit - as well as the 10AWG cable for the subs and some more cat cable and conduit for just in case.
You can also see evidence of further progress. The subfloor on the riser outside the theater entrance is much higher at this point - it has all three layers of subfloor installed, bringing it up to within a half inch or so of the finished height. You can also see the HDMI, two cat5e, and one cat6 cables hanging from the face of the soffit, waiting for a projector.