There is progress, it's just the slow kind. I have replaced the crystal socket with the proper one (and made an oversize washer for it to match the other ceramic sockets; it allows the retaining spring to lock in on the thin chassis metal) and installed one of the patch plates, with fuseholder.
Here's the busy bench:
And a better look at the underside of the chassis. I tinned a couple more spots for soldering ground connections, too: