This board doesn't get much activity since the Facebook page was created. I'd recommend you check out "Castlegate Community" via Facebook as there are FAR more participants there.
On the kids, it really just depends on what section you live in. My area has quite a few kids my son's age, but I know some of the sections have less kids.
On the concrete place, it makes noise, but it isn't enough for it to keep me awake when I'm sleeping or anything like that and I've never personally noticed lighting, etc from it.
I really do like Castlegate, but I've been in Ironwood Crossings (where the Fulton Homes are) and it's REALLY nice. It did not exist when we moved here, and personally, if I could live there I would. Their pool and splash pad is awesome and I like the layout better. However, their HOA dues are leaps and bounds above ours in order to maintain their pool and splash pad and such, so it's a give and take I suppose.
I do like the school (Simonton) in our subdivision. My son has gone there, just finished his 5th year there and will be starting his 6th year there in August. We've loved the staff, facilities, programs, etc. The LEAP program is great, they offer sports, band, choir, among other activities. And the HOA is doing quite a few subdivision improvement projects slowly but surely, so things have improved greatly.
Good luck in your decision!
Good luck!