You might want to check out some of the "easy packs" from Queen Homeschooling if you are a Christian homeschooler interested in a pre-made CM style curriculum. I use some of their materials, but am a secular schooler so I pick and choose on their site - I use their Lang Lessons series and have used their copywork/picture study books - really like all of these. I like the Queen's stuff - they really don't overdo it with the lessons and activities, leaving plenty of time to follow your own interests and make your own connections. And it is cheap.
I have Oak Meadow 3rd grade manual and some of the books - this was my original choice for a curriculum when I first started schooling my kids at home. I soon discovered CM and left off with the oak meadow book, but it is a good program and indeed very gentle. I would be willing to sell the book (bought it new 2 yrs ago), if someone would tell me how? I see people selling curriculum all the time, and I have a paypal acct, but I have never done it before LOL. I would only buy the items from the art kit that you could not find on your own - honestly we needed very little. I did buy the beeswax crayons and all that but my kids like to use everything, and these crayons are different but no better than good quality art supplies which you should have anyway, right
We did all the oak meadow reading selections though, but ugh - their peter pan book was abridged in the worst way! Their reading lists for each year are great - you could get the books yourself if you wanted or from the library.
Oak Meadow 3rd grade includes math BTW.
I don't see that combining different age students into family study is a goal of the oak meadow curriculum.
SOTW is the other curr. that I can comment on - this is a living book "style" textbook in my opinion - not a living book in itself. The activity book is nice and if you don't mind a textbook and a Christian POV it is good. But since we have discovered the joy of some true living books - we just finished "Boy of The Pyramids" - awesome! - it is hard to go back to the textbook style of SOTW. That said, many love it, and you might too. If you have the cds, go ahead and listen a bit before you invest in the additional materials.
You could definitely do family schooling with SOTW.
The only other thing I have to offer is to check out the free curriculum guide at Simply Charlotte Mason. I don't use it (although I use a lot of their materials and their forum is wonderful for CM info and advice), but it seems like a doable CM plan and they have some years available for order as handbooks - like lesson plans. They do put a priority on doing as much as a family as possible, so that makes the days easier.
Sorry to make such a long reply! I remember how hard it was to settle on a curriculum. I am sure you will make a good choice.