Well, now, here we are nearly a week later, and it is FINALLY working.
The power wire plugs into the accessory power plug behind the right front body panel. The power to that plug is protected by fuse #6 in the Right Fuse Box in the frunk. Yes, there is a left and a right fuse box in the frunk. In the Operators Guide fuse #6 is identified as GPS Acc with a rating of 5A (amps). The first time I finished everything and turn on the Spyder's key the face of the USB plug lit up with a blue backlight, just as it was supposed to.
But when I plugged in the power cable for my Garmin Zumo XT GPS it blew the fuse. There are several spare fuses mounted in the cover that protects the fuse box, including a spare 5A fuse. I swapped out the blown fuse and tried again. Same thing - blue backlight, blows when I plug in the GPS. I put the Spyder back together without the power working for the docking station, as I had a local event that I wanted to attend with my Spyder, which unfortunately wasn't much fun.
Afterwards, I pulled all the panels again, pulled the wire out, checked to make sure the wrapping was all still intact, and then ran it again to the accessory plug.
Since I had blown the only two 5A fuses I had, a quick trip online found a pack of five of the correct 5A fuses at a local auto parts store, so I bought them online, and when I received the "ready for pickup" email I drove down and picked them up.
Plugged one of the new fuses into the #6 spot, and then turned on the key. The USB Plug lit up.
So I plugged in the charging cable for my iPhone. The USB Plug stayed lit, and my iPhone said it was charging. I disconnected my iPhone and plugged in the Garmin Zumo XT GPS. The USB Plug stayed lit, and the GPS was indicating it was charging. I turned the key off, the USB Plug light went out, and the GPS indicated it was running on battery. And yes, one more time - key on, USB Plug lit up, GPS showed it was charging.
I am wondering if there was an issue with the two 5A fuses that came with my Spyder, since they both blew when I tried to use the docking/power station, but it works fine with a new 5A fuse I bought today from Autozone?
To be clear, I bought the docking/power station from slingmods.com, which came with excellent directions, it was just the fuse issue that was a problem.