Claim Jumper is also in the mall parking lot, on the South side of the mall and they have a GF menu.
Garlic Jim's pizza is also really good and I am guessing they would deliver to the Marriott.
Frankies Pizza has a GF pizza as well. I have not tried this one yet.
Sages has a gluten free menu.
Tyhpoon is a thai restaurant with a GF menu.
Wow, we do have a lot of choices!
I have also heard that Microsoft has some GF options in their cafeterias and, of course, the Whole Foods in Redmond has an amazing GF section loaded with tons of good food