M.D.
We love HIS ministries, a Christian classical homeschool group based/following The Well Trained Mind format for Bible, History and Science. There are 2 groups, Federal Way and Des Moines. In fact Tuesday at 7:00 we are having an informational meeting at the FW Reg. lib on 1rst Ave.
I know of others who love PATH co-op and ACTS co-op. Both of these offer a variety of classes. All of these meeet 1 x /week. I'm sure that there are more out there, WHO, WATCH and HSA are great resources. most will require your oldest to be at least 5, if not 6 to start, but it is great to get to know these now so you can plan, and even start getting to know the families to build relationships w/them and have those play dates.
Let me know if I can help you more.
M.