Wow, thanks for all the wonderful responses!
SewSewQuilter, I found the oilcloth online (Denver Fabrics or AH Mercantile). They have fabulous patterns. I used a heavy-duty needle meant for denim.
It was very easy to sew the oilcloth when the right sides were together, but difficult to sew once the right sides were facing out (the feed dogs had trouble moving it along). I had to pull the fabric through the machine manually. It was easier to have the fabic side of the quilt on the bottom and the oilcloth on top when quilting, since the feedgos were able to move the normal fabric.
For the quilt, I pieced the quilt top and then quilted it "in the ditch" with the muslin. I stitched on the oilcloth at the very end only around the edges (I spray basted everything to keep it in place). I simply turned under the fabric and muslin, which was the easiest way to do it. I pin-basted the oilcloth and fabric together, and the pinholes were pretty inconspicuous once the pins were removed.
Hope that helps, and best of luck with the tablecloth!