You have quite the dilemma.
When I moved states, I took a teaching position that paid less and had a lower retirement package with the trade off being it's the best or second best private school in the state. I've never looked back or questioned my choice. The pay difference was around $2500. The retirement compensation difference is larger.
To me, $2,500 salary cut wouldn't be your biggest issue. Yes, it's money, but it sounds like the positives of shorter commute, less stress, and having your wife there and your son at some point outweigh this amount.
I'm also less spooked by the district size. My previous district had probably 5000 total staff, at that level it all comes down to your local school and interactions with faculty and staff at that school and neighboring ones.
To me the biggest issue you'll probably deal with is the adjustment to the new culture and the technology issue.
Culture is tough everywhere: I've taught at four schools over two states and even within the same district, it takes a year or two to adjust. Luckily, with your spouse at the school, your curve will be less steep then mine was at each school.
Technology IMHO will be your biggest issue. This means, you'll have to reconstruct lessons and adapt to less technology while also adapting to a new culture. I would hate to go backwards in technology. I could do it, but the amount of work would suck.
Questions:
What stuff does your current school have that your new school won't?
Are there ways through budgets or grants to get you what you currently use?
Good luck! In all seriousness, I do believe either option will work for you and your family. It's nice to have two good options, none.