Hi..and welcome. Right there with you....the floor gets further away every year !!!!
I have a fold up cardboard "thingy" with a grid printed on it that measures about 44" x 72" - you can buy them at JoAnn's. I'm sure it has a simple name - but like the floor - nouns are getting harder to find !!! They are fairly cheap. I put that on my table - and it extends the size of the work surface...(and protects the table) That might help.
But if it were me...i'd use the Elmer's school glue method to put my backing, batting and top together. You have to work in segments anyway with the glue - i usually start with laying out my batting and folding the backing in 1/4 segments. Glue - let dry - then repeat with the top. I always make my backing larger than my top by a 3-4 inches - and don't cut away the excess til it's quilted and ready to bind. Shorted myself one to many times once the quilting was done.
Best of good luck !!!