Hello Z7E. I don't know if you have considered going south to Georgia. In DeKalb county we have in our public school system a magnet program for all gifted kids. The school starts in 4th grade and goes by the name of Kittredge Magnet School. It is all gifted/accelerated kids with testing requirements to enter. Unfortunately it is a lottery after that and only serves about 10% of those who qualify due to capacity. I had one of my kids win a lottery spot and two did not. It was everything I hoped for and more. We also have private schools here. The top private schools people recognize as the greats down here (Westminster, Lovett, PACE, etc.) are expensive $25K/yr/kid and do no acceleration. We were disappointed on many fronts.
They get better in middle and strong in high school but elementary is weak. There is one private school - Fulton Science Academy Private School (Alpharetta GA) that starts at pre-K and goes through 12th. They serve only gifted/accelerated and have kids moving up grades and course levels everywhere. They start an 18 month math track (in normal 12 months) in 1st grade allowing a kid to jump a 1/2 year per year. This school is $12-13K/yr so much more reasonable. All 4 of my kids have been there and I currently have my 2nd grader there (working on 4th grade math - ahead of their most accelerated path). For high school we also have dual enrollment down here allowing your Junior/Senior in HS to complete 2 years of college in parallel with high school for free. Also, we have free tuition to in state schools (GA Tech, UGA - 2 top 50 nationally ranked schools) to name a few if you graduate HS with a 3.7. We are from MA originally and while it took some time to look we are really happy with our options in GA for gifted schooling. All 4 of my kids have needed this. My oldest (14 yo) starts at GA Tech for Engineering in June and will enter as a Junior. A great success story.