If you think you'll do this often (3-4x a year) it might be worth considering the purchase of a folding office table like these. They come in handy for SO many things. I use a self-designed 40" x 72" table to baste my quilts. I clamp the backing down first; lay the batting over that, remove each clamp individually and reclamp over the batting and backing, keeping both layers smooth and gently taut. Lay the top over that, again reclamp each one individually, smoothing as I go. If any hangs over the edge, that's fine. I baste (by pin, by thread, or with glue) in the area that is clamped; move the quilt to accommodate the undone area, reclamp, and baste again.
http://www.officedepot.com/a/product...d-Plastic-Top/
Jan in VA