Any price range? My mother is that age and diabetic so no sweets for her. But she loves orchids and has several growing in her house. Perhaps a flowering potted plant for your co-workers desk? Hand cream is another nice gift for my mother b/c older people tend to get dry hands especially in the winter. A manicure gift certificate is also a nice idea. If you know what kind of music she likes, a cd might be appreciated. But not an itunes gift card. That generation, generally speaking, does not do ipods.
A snake plant. Unbelievably hardy. I had one in a corner, I didn't touch it for months. I finally killed it... by watering it! It'll surely be fine for a couple of weeks. Another plant that does well with little attention is a Peace Lily.I know she's traveling for 2 weeks at Christmas so I'm not sure an orchid would be a good idea -- but I think it's a FABULOUS idea in general. Maybe I can use that idea for someone else.
Too late now, but you could have started a conversation about the benefits of "regifting". How it can save money... how, most of the time, people purchase gifts for others that they like themselves... then have somebody else (can't be too obviousI bought that 2 years ago for my aunt. Saw it over the Thanksgiving holiday in her house with the tags still on it. I really wanted to swipe it!
Does she like the movies? Some theaters sell a gift pack (tickets for 2, drink, popcorn)
) mention, "Oh, isn't that the bag DisneyandRedSox bought you?" 
