Here's what I wish I'd known in advance.
It's fiddly to set up but it really does work well.
You can expect slight visual artifacts at the edge of your peripheral vision, but otherwise perfect visuals, and perfect tracking except with ~4ms of extra latency. This isn't noticeable, but made me feel a bit woozy at first. I appear to be adapting.
Basic architecture: Video and USB are sent completely independently. The HDMI video goes over a 60Ghz connection to the receiver on the top of your head. The USB (position/orientation) goes over a normal wifi connection (I kid you not) to the "power box" (actually a raspberry pi) clipped to your hip. Power is supplied by an off-the-shelf Anker USB battery.
You can remove the "link box" that came with the Vive. Your connections should look like:
[PC]==hdmi==[TPcast transmitter] - - 60Ghz - - [TPcast receiver]==hdmi==[HMD]
[PC]==cat5==[TPcast router] - - 5Ghz wifi - - [TPcast power box]==usb==[HMD]
Audio goes straight from the HMD to your headphones as usual.
The TPCast transmitter can use the 12V power source that used to drive the link box.
In terms of actual cable routing on the HMD, there are a bunch of youtube videos out there that cover it. I used this one: https://www.youtube.com/watch?v=5178KnQst74 .
It's theoretically possible to use your own wireless router instead of the supplied one, but I found that the increased latency was unacceptable. So yeah, you are setting up an extra wifi network just to talk to the TPcast power box.
The official software, if you can even find it (and there are multiple versions), is garbage. Don't bother; go straight to OpenTPCast. Follow the instructions here: https://github.com/OpenTPCast/Docs/blob/master/guides/UPGRADE.md . It'll take half an hour or so and cost $USD25.
OpenTPCast works out of the box. You don't even need to configure the wifi settings - it comes preloaded with the SSID/password used by the TPCast router.