I say if you're looking for an alternative to Autism Speaks for a child, then a pile of "fact books" about how things work, a stack of sci fi/ fantasy books at age level, and a box of art supplies should do just nicely.
Homeschool them, and let them work at their own pace and follow their passions, and they'll soon be way above grade level in some subjects. In subjects like History or Science, just let them read the books, and tell you all about what they learned. An autistic child doesn't need worksheets or tests in order to record facts. I promise you will hear a long, rambling speech about every nuance in the chapter, and they will be reciting it to you on car rides for months to come.
The learning might be slower, but the child will learn much more in depth and will retain that knowledge better.
I would say parents should quit looking for "autism support", and telling everyone your child is autistic, looking for sympathy. Instead, tell your child they are autistic, and list the greats of history who probably were too. Make them feel excited about being a "genius" and let them know it's okay to be socially awkward, and that solitude can be really fun, because you can be in your own private world.