TSA won't be a problem. In the unlikely event UA is, gate check the roller and pick it up at the gate on the other end. I usually board early and keep the items on the other side of my body or the computer bag on top of the roller bag. They have not questioned me once...

Well in YVR their TSA did question me after than pulled me for a random. "Seems like you have way too much stuff here sir... I explained one of the bags was the duty free purchases (which they were). I insisted they didn't count. The guy gave me a tough time but finally left me alone. I said yes sir, no sir and all that good stuff but he went through my stuff extra slowly to upset me. I had two hours. He wasn't going to get me.