As I said in a comment on that post,
I did get a solution. BusyMac's BusySync. It is not free, but it is only a one-time $25 purchase to do what I want to do. My iCal calendars easily publish to calendars on Google, and I can share them with my wife (and others).It was straightforward and easy to set-up. On my Google Calendars I set up calendars to match the calendars in iCal—just the ones I want to synchronize— and that are synchronized with my iPod touch. I even picked the same colors. After that I just follow the very easy to follow pointing and clicking in BusySync, connecting iCal calendars and Google Calendars. iCal does not have to be running. Periodically, BusySync syncs iCal and Google Calendars. It sits up in the menu bar and periodically spins for a few seconds.
Now, away from my Mac at home. I have access to my calendar on my iPod , as well as on Google Calendars.
I can change the calendar in either place. Doing it in Google Calendars means that anyone I share my calendars with can see the updates. It automatically syncs up to iCal at home and when I plug in at home, it syncs down to my iPod as well.
Exactly the behavior I was looking for. It's not free. But, the $25 cost of the software is well worth it to me.
See the BusySync User Guide.