Aurifil is two ply so you may have to loosen tension and switch to a larger needle size to account for it being a weaker thread than three ply 50 Wt. Other than that, you should be fine.
Additionally there is no need to drive 100 miles for quilting thread when there are so many on line sources available that will deliver to your door. Granted you won't get it in time to finish the quilt in two days, but I would recommend stocking up now so your are all ready for your next project. enabler that I am, here are just a few links to get you started. Metro Embroidery thread works great for quilting and you won't find a less expensive thread anywhere out there. All the others are wonderful sources as well. Bobbin central requires a $35 minimum order. If you want to order less you can find retailers that will sell you one cone at a time. Just Google Glide thread.
http://www.bobbincentral.com/
http://metroemb.com/store/
http://redrockthreads.com/
http://www.superiorthreads.com/
http://www.connectingthreads.com/thr...g_threads.html