i would definitly recommend either quilt as you go- or quilt it in sections which you then join---something that large will be impossible to reach the center of on a domestic machine- few long-arms are even large enough to (comfortably) do one that large.
the largest quilt i ever made was my daughter's wedding quilt- it was 126" X 140"! i paid ALOT to have it long arm quilted (as in over $400)