I can quilt a twin quilt comfortably on my Bernina 440. A queen is a bit of a stretch but I quilt it in quarters so I only have one quadrant in the machine at a time. (I just finished a 94 X 94) I use Hobbs 80/20 fusible batt and it helps me to not get wrinkles on the quilt back and it reduces bulk. My Machingers gloves really help me move the quilt well and I support the rest of the quilt on extra tables.
A long arm will be easier of course, if you can afford it.