I am currently machine quilting a king size on my machine (Janome 6600). I have free motioned a queen on it already. This one will take a bit longer than planned as I find a couple of hours at a time is enough! I have changed the quilting ideas I had for it to a simpler pattern and infills than I originally planned to do, but it is going okay. I have a left hand corner with tables in front and to the left of me so there is plenty of support for the quilt.
I did get a Sewslip mat recently and that has made a huge difference to doing free motion.