I couldn't speak to going back to school or not. But relocating with young children... when they're still young is a GREAT time to relocate!
It's much harder on them when they're older (speaking from someone who moved long-distance at age 6 - easy; and again during sophomore year of high school - harder). Not that you *shouldn't* move when they're older, either... just that it's harder... in my case, I think it actually helped me by making me stronger.
What I'm saying is, don't worry about the relocation angle, it'll be fine, esp if you go in with a positive attitude like it will be an adventure. I also think the moving helped me a lot in understanding that we don't have to spend our lives in the same city we were born in or grew up in. With that attitude, a child grows up feeling like they can do anything in their future - they're not limited to a specific place!
Sorry for the super-long answer on just one aspect of your question... but this was all I felt qualified/able to help with. Ultimately it comes down to the whole big picture of what's best for you and your family. I'm keen to hear what others have to say.