I bought an 8ft long table with folding legs. It's 30 in wide, but the lenght means that the quilts I generall do don't hang over the ends. I have large clips that hold the backing taut on the table, with most of it over the back of the table. Drape the batting and top again with it flat on the table (held with the clips, and the majority over the back.
Pin baste, or I use a microtack gun, all over what is on the top of the table, then loosen off all the clips, pull the three layers towards you, re smooth, re clip, and baste what's on the top of the table again. Repeat until you get to the far side of your quilt.
Downsides? I can't lift the table by myself. I had intended to store it in my garden shed but so far, it has stayed propped up against a wall in my hallway. Upsides, I sat down to do the whole lot, no aching knees or back, no creases on the back.