These two memory quilts were posted here yesterday.
I thought this one was incredibly effective (yet very simple to make).
http://www.quiltingboard.com/t-143075-1.htm#3878480
And this was a different use of ties than traditionally seen.
http://www.quiltingboard.com/t-143248-1.htm
Although I do think your idea of using them as strips will work very well.
You can combine the two into one quilt.
Don't over think it - the quilt doesn't have to be made up of very complex blocks.
The first quilt above, while just made up of bricks, will be incredibly meaningful to the widow (and family).
It's a very nice thing you're doing.