Now that the weather has warmed up some, I went to install the XM set in the car Tuesday evening. I ran into a problem: there's no good place to put the XM radio in a Corolla, even with the various mounting options that came with the radio. After some frustration, I did the Googling that I probably should have done earlier. It looks like the best way to mount the radio is with a bracket made for cell phones. I ordered one yesterday and hopefully it will arrive no later than Saturday so I can install it this weekend. Watch it arrive Monday.
Last night I decided I could at least get things started and deal with antenna placement and some cable routing. That went rather well. Setting things up in a temporary manner, I was able to use the XM set (placed awkwardly in a cup holder, but at least it wasn't sliding around) and go for a drive to see how things were. Things were very well. The XM set had good reception and the re-transmission to an FM channel worked well.
Other than the mounting bracket, I still need to deal with how everything is powered (I had to disconnect my mp3 player to power the XM) but that shouldn't be too big of a deal.
Ideally, this will all get done before the Easter weekend when I'll be on the road for several hours. It will certainly get done before RCFM.