Compounding the uncertainty of finding the right school is knowing that many parents end up trying multiple educational options before finally finding what works best..or...is the least-worst option. I found this survey on educational options for HG+ kids quite interesting.
http://www.growminds.com/ed_options/summary.html
My current plan for DS is to join the Seattle Homeschool group while also attending school p/t and see what option naturally unfolds over the next couple of years as best suited for his needs. He�s only 3.5, so the DS 2 years from now will be so different from today that I hope the right educational choice will be much clearer, and, of course, he will have his own strong opinions.
Below is an article link you may be interested in regarding homeschool in Seattle. The great thing about Seattle is that there are so many enrichment activities available here as young as 5 (math circles, UW Robinson weekend courses, chess classes, lego leagues, drama school, art schools), that it may make it a little easier to find peers with similar interests.
http://www.seattleschild.com/article/homes-cool-four-homeschool-approaches