Well, I'm pleased to report that after sinking an excessive amount of time into this project and stumbling through all of the gotchas detailed in the previous two installments, I finally hit upon a set of products and a work flow that resulted in really nice quality output as follows:
As I stumbled through all of this, I found I was following in the footsteps of a great many others who had experienced all of the same issues I had with these various products... In the end, the whole experience told me that while many of the scenarios I was working through aren't yet ready for the masses, the Longhorn planners really are on the right track for the next release of the world's preeminent consumer desktop operating system. It's the right time to bring together all of the advancements in hardware, software, and media and wrap it up in a package that is easy enough for my mom to use. Thanks to all who offered advice and help along the way.
There already is a solution that is easy enough for your mom to use - it called iMovie, only available for OS X though :)
I run the analog signal through my Sony Digital camcorder which converts it to DV which I import via the built-in firewire - easy enough for your mom!