You should get Harriet Hargrave's heirloom machine quilting book. She was one of the first people that started machine quilting in the early 80's. Her work is beautiful and she does King and Queen size quilts with a regular bernina. She has great tips. You should be able to get it at the library, she is terrific.
I am just starting to really machine quilt after 20+ years, but after reading her book. I feel I can do it with my Bernina, and not have to buy a longarm. But it is all preference.