Cela--
Yes, you can really be as flexible as you want using Sonlight. People are all over the map on what they think about it, but I have found that the company itself is very easy to work with and very supportive of doing what's best for your family.
I just can't say enough about the literature they offer. Being a bit of a "classics" snob, I have thoroughly enjoyed reading books to the kids that I never picked up when I was a kid or would have incorporated into my own lesson plan. We just finished "Across Five Aprils", for example, where I learned more about the Civil War than I ever did in my own studies. ;-)
One of the things I love best about Sonlight, besides having it all laid out for me, is that it's intellectually honest but with a Christian worldview (so at the very least our faith isn't ridiculed--at the same time, it shouldn't be held up without a blemished past, if you know what I mean); Charlotte Mason with a bit of classical thrown in; lots of great literature and reading; a bit of unschooling for good measure; and incredibly supportive with what I think are some of the best homeschooling forums around!
I've also heard that Tapestry of Grace has great reading lists, although I've never personally explored them.
:-) Cate