Just wanted to blab about my playtime this weekend...
I was able to hook up that Linksys to a separate network using a USB wireless adapter that I had in my box of "rejected hardware". I used the ad-hoc mode on each and while apparently ad-hoc connections are limited to 11Mbps it played videos just fine.
The last thing I need to do is test out the range to see if the USB adapter can handle the distance to my main TV. I found it to be lacking when I tried to use it for my notebook. I also found that the antenna is loose on the Linksys so I get to practice some minor soldering. Though it is working without it.
This whole thing has been really fun. I'm so close now.