Prism99 suggested this and I did it on my avatar Steeler picture.
You can also split the quilt into 3 parts (without the division showing later) to make the bulk easier to handle. To do this, you layer the sandwich as usual, pin back a third of the top and backing fabric so it is out of the way, then cut the batting only in large S-shaped curves. Mark both sides of the cut so it is easy to reposition the two pieces later. (The curving cutting line helps with the repositioning later and also hides the join.) Pin the top to the backing fabric. Do the other side of the quilt the same. Machine quilt the middle section, leaving a good 4 inches or so free near the cut edges. When the middle is done, re-attach one side of the batting with hand tailor tacks (or some people do it with a long and wide machine zigzag) and re-position the top and backing over that section. Complete the machine quilting on that side. Repeat with the other side. Marti Michel has a book on how to do this, but I first saw this process described in detail in another book by another quilter (whose name escapes me at the moment).