A lot depends on how closely you are quilting. I make at least 20 Linus quilts a month and those are machine quilted on my Bernina with a decorative stitch about every 4 inches and then about 1/2 around the edges to create a false binding. I can usually do one of them in about an hour. Anything larger I prefer to handquilt. Again a lot depends on the closeness of the quilting. I am a domestic goddess and can spend as much time as I want on quilting. I could handquilt a quilt that size with a decent amount of quilting in two to three weeks. I get a lot of TV watching in at the same time. For something that size I would use my round floor frame that resembles a large embroidery hoop on legs.
I do have 40 years of experience quilting.