This is the process I use all the time. I have one of the craft tables similar to those available at JoAnn's. It's not overly large and I've done king sized quilts on this table simply by carefully shifting as necessary. I start in the middle, pin, move the bulk of the quilt to one edge, making sure that a reasonable amount of the previously pinned area, clip and proceed. It's far easier on the back and certainly on the knees as opposed to doing it on the floor!

i use both the floor and my kitchen table. If I use the floor I will use masking tape to hold down the corners and try to instill smoothness. I hand quilt so I can smooth out the wrinkles as I go. It is hard to sandwich no matter how I do it.

Try this. This works for me
http://www.youtube.com/watch?v=bhwNylePFAA

In the summer, I use the hose to spray with water our driveway. When dry, I use pkging tape to tape down the backing wrong side up. After using spray in layering the quilt, I pin it.

No wrinkles, and it machine quilts great!

This is how I do it too. Start in the middle and work to the sides. I've done it with pins and with spray.

Good Morning. I have same problem for very large quilts.

I bought a large vinyl flannel table cloth, lay in on carpet flannel side down.
Adheres to carpet very well. Also when new cloth I run it in my dryer first, low temp, to get rid of wrinkles. Watch it carefully so not to get too hot. Use safety pins to hold quilt down smoothing all the way. Works pretty well for me and not so hard on the knees.
A Helper would be good. I don't have anyone to help so it takes longer.

Harriet Hargrave recommends doing it on a table. She describes it in detail in her book "Heirloom Machine Quilting."

She recommends taping a toothpick on the centers of the top edges of the table. You can then feel through the layers to know exactly where the center is to place your sandwich layers.

I used to use my dining table with leaves in- gave me 36x72 space. I went to Home Depot w/DH and got some of the big clamps like he uses for wood projects. Lay your backing down, centered with pins at the center, using length of table for width of your quilt. Smooth out and clamp on both sides, then lay batting, centered, and top, again centered. I then pin with large safety pins about 4-5 inches apart, working from the center out. You have to unclamp and slide the entire "sandwich" first one direction to continue pinning, then back the other way. If you take your time with smoothing and clamping, then flip to check the backing once it is all pinned, you should be good. May have to redo some of the pins, but usually it is out near the edges. I now have a top that DH made from a sheet of plywood that fits over my table-gives me a 4ft x8ft surface, still clamping and pinning.

I know some people say "This is wrong." but.....
(I don't listen to quilt police.)
I put the top onto the batting ONLY. I quilt a little bit, then after that, I take the backing and quilt it to the other two layers. Voila! NO PUCKERING!!!
And now, I have discovered QUILT AS YOU GO where you actually sew your pieces of the top to the batting as you go along. Why didn't I find that some years ago??? It works out amazingly! Before you know it, your top two layers are done and you are ready to add your backing. No three layers for me. I enjoy my working and my work much more when I use these methods. Why torture yourself and the quilt?

I have a long table that I use. I tape the backing down along the short edges and then lay the batting on, smoothing it well. Then I lay the top and start working. I do use clips along the edges sometimes. The best thing I bought for myself was the bed raisers that they sell with the "college stuff"-you can lift your bed up so things can be stored under it. Found a set at JoAnn fabrics for $10 and it makes such a difference on my back!