Ring Around The Phonics (4 years old through 6Th grade) is a language arts board game / curriculum that is very hands on (Whole Brain Teaching). The static cling letters make the game very flexible allowing you control what each child needs to learn. You can teach up to 4 children at one time even if they are on different subjects/ levels.
We use story of the world and love it. Ut was written by a catholic woman, but our charted will not pay for anything religious and they paid for this. So far it has not seemed religious. It covers history, geography ans has book suggestions based on what the subjecy is, im sure you can get the books atvthe library. The kids are learning about the egyptians and fertilecrescent and they did their names in heiroglyphics on a paper scroll yesterday. They also colored in a map of egypt, sumer, mesopotamia etc.
What about getting those DK Eyewitness Books and putting each set of books into a study? Like for say Religion you can take all those books they have on individual religions and then make a study out of that. Or if you are starting ancient civilizations you can get the DK Eyewitness books for that and do stuff with those books. A Trip Around the Wold series you could do for hands on Geography/Social Studies. They have 4 books.
Since it is for first grade, I would just purchase Evan-Moor workbooks to use for the Language Arts. We didn't start a formal L.A. curriculum until second grade. For the SS/G, I would use living books. Rebecca Rupp's book Home Learning Year by Year gives excellent grade guidelines for what you should be covering and book titles. We always put History/SS together with Geography. Great reinforcement to find the location on your world/U.S. map of whatever you're studying.