Unless a SLC LBS has a case in stock, your only option is probably to get your bike packed by your LBS and ship it to your hotel. While you are in Decatur, you should be able to either find a case at a DFW LBS or order one online and have it delivered to your hotel. You'll then have it for the return trip and furture trips.

Keep in mind though, that unless you pay big time for something like 2nd day delivery, it's might take a week to get your bike to Decatur, leaving you only two weeks to ride. If you are working all day, then you may only get significant riding on the weekend. Consider if you will ride enough to make the cost worth it. Consider that sunrise is about 7:15AM and sunset about 6:00PM while you are going to be in Texas. It may be better to rent a bike from Richardson Bike Mart for the weekends assuming the weather is acceptable.