So, to focus on the relocation issue...

While I agree that education isn't the only thing you consider when you move, it is a consideration. So here are some things to think about:

http://www.davidsongifted.org/db/StatePolicy.aspx

This map shows the status of gifted education in each state. It makes sense that a state that both mandates and FUNDS gifted education may have more options. Note that states that mandate but don't fund may only be paying lip service to gifted education (hello, Oregon). Click a state for more information.

http://www.nagc.org/resources-publications/gifted-state

This site has links to each state's department of education and gifted department and laws and details.

https://www.hslda.org/laws/

The education of last resort for highly gifted kids is sometimes homeschooling. This site lists the laws for each state. Some states have more religious homeschooling and some more secular. If this distinction matters to you, then I recommend checking into that as well.

While big cities have more educational options, they may also have districts of high achievement striving that can harm access to gifted specific programming. Basically, some districts are so used to every parent thinking their kid is gifted and special that they are sick of hearing about it. Whereas a smaller flexible school district may be thrilled to have a super bright kid.

Remember, in the end it's the school and the principal and teachers that matter the most. My experience is that some people get it and some don't and the ones that don't probably aren't.