Thanks to everyone who posted. I should have included in my original post that we are in Michigan, where it is very easy to homeschool, and the kids are going into 3rd and 4th grades. We want to homeschool because they are both enthusiastic, independent learners, but they waste too much time in school waiting for everyone in the class to reach the same level. They also have specific interests they would like to pursue in a more in-depth way, but school leaves less time and less money for this. I work a very flexible, very part-time schedule, so I think this can be done. They can even go to work with me if necessary.
Thanks again, everyone.
Best wishes to you and your fortunate third and fourth graders as you embark on your adventure of learning together! Yes, you will learn from them, too, and discover that the schools to this point have certainly missed some important areas, so don't feel intimidated. My daughter has just finished her first year of schooling our 5th and 7th grade grandsons, and she found this to be true even though they had paid tuition at a pricey private school. Their year went so well that they are looking forward to doing it again this year. She used Saxon for math and Abecka for everything but Texas history. God bless Texas for giving parents the utmost freedom in educating their children as they see fit.
You might check out KONOS at www.konos.com for a very action-oriented, all-inclusive curriculum. The units are topical, and there are sure to be units of interest to your kids. I love that their focus is on character traits -- orderliness, obedience, patience, just to name a few. The units teach that trait using Bible stories and verses and then show how it is applied in numerous sub-units, such as animal/plant/rock classification, birds, kings and queens, the five senses, ships, etc. The curriculum covers every subject area and you need to only add math curriculum for a well-rounded education.
Just my 2 cents here, if you want a comprehensive curriculum that sort of "holds your hand" on being sure you have everything foundational covered, I would recommend Alpha Omega. they have what's called "Lifepac" sets or what we use - a set of software called "Switched on Schoolhouse" which is all done on the PC (except for writing assignments built into the lessons).
A complete set for a year runs roughly $300 - less depending on where you buy it, and the beauty of it is, if you use the soft ware, after the first year you only have to buy one set because your second child can use the same one your oldest used last year.
Then, once you are comfortable with the routine, you can supplement it as you want to in order to follow your child's specific interests.
Another good thing about it is that it is ideal for a difficult schedule because the child can be an independent learner on most of this work.
It works great for us (my oldest has done fifth and sixth grade on SOS).