We've done this in the past, and surprisingly, if we waited that first 30-45 mins until she was sleeping soundly, we could then make a degree of noise without DD waking. The other thing I found useful was to use an extra blanket draped over the side of the cot facing towards the light (most motel lights are mounted on teh wall and not overhead) to block out any light that might wake her. But there again we were always pretty noisy and expected DD to sleep through it, the thing that made the difference was the amount of light in the room.

Maybe experiment before then by putting Ella down one evening in the portacot in the loungeroom before you go o/s, and see what works and what doesnt...?